IRS-A2A BulkRequestTransmitter message not formmatted properly and/or cannot be interpreted

Question

I am receiving the following error when attempting to submit through the BulkRequestTransmitter Web Service. The Composition Guide is less than helpful as far as this message goes, and when I compare my SOAP XML with the SOAP from the Composition Guide, they seem to be apples-to-apples. I'm hoping that another set of eyes may be able to see where the problem is.

The message was not formatted properly and/or cannot be interpreted. Please review the XML standards outlined in Section 3 of the AIR Submission Composition and Reference Guide located at https://www.irs.gov/for-Tax-Pros/Software-Developers/Information-Returns/Affordable-Care-Act-Information-Return-AIR-Program, correct any issues, and try again.

What I've Tried:

• Attempted to submit with (and without) whitespace in the SOAP Envelope.
• Attempted to submit with the Form Data XML in XML format.
• Attempted to submit with the Form Data in base64string format (as this submission was).
• Added the ds prefix to the Signature elements. Used this SO post in order to add the prefix to the Signature elements.
• Added the Form Data in "Pretty Print" format and as according to the updated Composition Guide (v4.2).
• Copied the formatting of the MIME for the BulkTransmitterService request outlined in section 10.3 of the Composition Guide.
• Created two solutions: 1.) Manually creating the XML necessary for the SOAP requests and sending via HttpWebRequest object; 2.) Sending a submission request via the WSDL imported to the project as a Service Reference, using custom encoders for GZip and Mtom Encoding and manually creating the XML necessary for the SOAP Status Request (sent via HttpWebRequest).

Update #1
Updated the request based on some new additions.

• Added the ds prefix to the Signature elements.
• Added the Form Data in "Pretty Print" format and as according to the updated Composition Guide (v4.2: Section 5.4.2).

Update #2
I began to manually create the SOAP .xml file within a new instance of Visual Studio importing the schema references as necessary. I'm doing this outside of any sort of application creation.

In doing so, I was able to find some additional bugs in the SOAP I was creating through my application (thank you for intellisense!). The bugs that I found were within the Manifest XML, as they didn't conform to the IRS schema.

I will be looking into these in the next 24 hours and update accordingly.

• The urn:MailingAddressGrp should have a child of either urn:USAddressGrp or urn:ForeignAddressGrp. That child should then contain the proper address elements. My code is currently missing the direct child of the urn:MailingAddressGrp.
• The value for urn1:DocumentSystemFileNm of Form1094C_Request_[TCC]_yyyyMMddThhmmssfffZ.xml is incorrect. I'm not entirely sure what it should be just yet.
• The urn1:BulkExchangeFile element, is having an issue related to the xop:Include element I have within. The schema wants a base64Binary type.

Update #2.5

• Updated my XML generation process to include the USAddressGrp element.
• Discovered that I had one extra character in the milliseconds (four instead of three). Once I corrected this, along with removing the string "Form" from the beginning of the file name, the value for the urn1:DocumentSystemFileNm was able to validate against the schema successfully.

Update #3

• Updated the Full Request based on the updates I have made. At this point, I am unable to deduce what is wrong with my request. If anyone sees anything glaring, please help!

Update #4

• Updated the Full Request based on additional updates made. Removed the ds prefix from the Signature based on another SO user's feedback. This user has gotten these requests to work without having to append the ds prefix to the Signature after the fact and re-compute the signature.

  The SO user also confirmed that his requests are working with an <inc:Include> element being setup as a child element of the <BulkExchangeFile> element.

• Confirmed the MIME headers are correct as per the sample in section 10.3 of the Composition Guide.

Update #5

• I currently have two solutions: one which is sending manually creating the XML necessary for the SOAP requests and sending via HttpWebRequest; and one which is using the WSDL Service Reference for the Submission Request, using the custom encoders outlined below, and manually creating the XML necessary for the SOAP Request of the Status.

  As of this update, Solution 1 gives me the error above when making a Submission Request, and gives me the error below when making the Status Request. However, when using Solution 2, both requests (Submission and Status) give me the error below.

  I am looking into possible certificate issues to see if they make any progress with either of these solutions.

Update #6

There were a number of issues I ran into which caused me to be delayed. I'll spare you the nitty-gritty details, however, the short of it is that we did not have the Security Certificate registered with the IRS system, nor did we have the Certificate installed properly so that I could access the information through the X509Store. Finally these things got done, and I was able to test submitting data to the IRS from the server (vs. my localmachine which did not have the proper certificate). Unfortunately, I am still receiving the WS-Security error detailed below. I have updated the Full Request with what I am currently sending.

An Error Occurred with message: The WS Security Header in the message is invalid. Please review the transmission instructions outlined in Section 5 of the AIR Submission Composition and Reference Guide located at https://www.irs.gov/for-Tax-Pros/Software-Developers/Information-Returns/Affordable-Care-Act-Information-Return-AIR-Program, correct any issues, and try again.

---

All line breaks in the MIME headers are as-is, and I believe the line breaks are what is expected. The FormData attachment is being sent as Pretty Print while the SOAP Envelope is not; The SOAP Envelope in this post is formatted for readability.

UPDATE #7:

Thanks to users: jstill and fatherOfWine with what they have posted below, and to Bon for earlier assistance on this project. I have broken through one wall in getting the Submission to work. It is now working. The Status request is also working. However, I need to figure out how to process it in order to pull the status and the attachment (error data file) out of it.

Full Request:

Content-Encoding: gzip
Accept-Encoding: gzip, deflate
Content-Type: multipart/related; type="application/xop+xml"; start="<rootpart>"; start-info="text/xml"; boundary="MIME_boundary"
SOAPAction: BulkRequestTransmitter
MIME-Version: 1.0
Host: la.www4.irs.gov

--MIME_Boundary
Content-Type: application/xop+xml; charset=UTF-8; type="text/xml"
Content-Transfer-Encoding: 8bit
Content-Id: <root_part>

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Header>
        <Security xmlns:h="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
            <Signature Id="SIG-E77c57b78ebc54e989bfc9e43604a04a4" xmlns="http://www.w3.org/2000/09/xmldsig#">
                <SignedInfo>
                    <CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#WithComments" />
                    <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
                    <Reference URI="#TS-Eb4799bee41bb4df0a72f52832d283ef7">
                        <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
                        <DigestValue>[TimestampDigestValue]</DigestValue>
                    </Reference>
                    <Reference URI="#id-E5f1ed32aab8f4578adeee5debd851a62">
                        <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
                        <DigestValue>[ACABusinessHeaderDigestValue]</DigestValue>
                    </Reference>
                    <Reference URI="#id-E4a71164001994d7f865fc7ddb8055350">
                        <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
                        <DigestValue>[ManifestDigestValue]</DigestValue>
                    </Reference>
                </SignedInfo>
                <SignatureValue>[SignatureValue]</SignatureValue>
                <KeyInfo Id="KI-E2309cb142e1a4076a2e71373e6e6b75f">
                    <SecurityTokenReference d6p1:Id="STR-E2751169ee468470290fe5e8bfb34589e" xmlns:d6p1="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
                        <KeyIdentifier EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary" ValueType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509v3">[KeyIdentifier]</KeyIdentifier>
                    </SecurityTokenReference>
                </KeyInfo>
            </Signature>
            <a:Timestamp a:Id="TS-Eb4799bee41bb4df0a72f52832d283ef7" xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns:a="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
                <a:Created>2016-05-18T09:51:05.856Z</a:Created>
                <a:Expires>2016-05-18T10:01:05.856Z</a:Expires>
            </a:Timestamp>
        </Security>
        <ACATransmitterManifestReqDtl a:Id="id-E4a71164001994d7f865fc7ddb8055350" xmlns:h="urn:us:gov:treasury:irs:ext:aca:air:7.0" xmlns:a="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns="urn:us:gov:treasury:irs:ext:aca:air:7.0">
            <PaymentYr>2015</PaymentYr>
            <PriorYearDataInd>0</PriorYearDataInd>
            <EIN xmlns="urn:us:gov:treasury:irs:common">000000301</EIN>
            <TransmissionTypeCd>O</TransmissionTypeCd>
            <TestFileCd>T</TestFileCd>
            <OriginalReceiptId />
            <TransmitterNameGrp>
                <BusinessNameLine1Txt />
            </TransmitterNameGrp>
            <CompanyInformationGrp>
                <CompanyNm>Selitestthree</CompanyNm>
                <MailingAddressGrp>
                    <USAddressGrp>
                        <AddressLine1Txt>6689 Willow Court</AddressLine1Txt>
                        <CityNm xmlns="urn:us:gov:treasury:irs:common">Beverly Hills</CityNm>
                        <USStateCd>CA</USStateCd>
                        <USZIPCd xmlns="urn:us:gov:treasury:irs:common">90211</USZIPCd>
                    </USAddressGrp>
                </MailingAddressGrp>
                <ContactNameGrp>
                    <PersonFirstNm>Rose</PersonFirstNm>
                    <PersonLastNm>Lincoln</PersonLastNm>
                </ContactNameGrp>
                <ContactPhoneNum>5559876543</ContactPhoneNum>
            </CompanyInformationGrp>
            <VendorInformationGrp>
                <VendorCd>I</VendorCd>
                <ContactNameGrp>
                    <PersonFirstNm>ContactFirstName</PersonFirstNm>
                    <PersonLastNm>ContactLastName</PersonLastNm>
                </ContactNameGrp>
                <ContactPhoneNum>ContactPhoneNumber</ContactPhoneNum>
            </VendorInformationGrp>
            <TotalPayeeRecordCnt>3</TotalPayeeRecordCnt>
            <TotalPayerRecordCnt>1</TotalPayerRecordCnt>
            <SoftwareId>PPACA</SoftwareId>
            <FormTypeCd>1094/1095C</FormTypeCd>
            <BinaryFormatCd xmlns="urn:us:gov:treasury:irs:common">application/xml</BinaryFormatCd>
            <ChecksumAugmentationNum xmlns="urn:us:gov:treasury:irs:common">6b2512ce28f603f76261923d297738e5</ChecksumAugmentationNum>
            <AttachmentByteSizeNum xmlns="urn:us:gov:treasury:irs:common">14076</AttachmentByteSizeNum>
            <DocumentSystemFileNm>1094C_Request_[TCC]_20160518T215105716Z.xml</DocumentSystemFileNm>
        </ACATransmitterManifestReqDtl>
        <ACABusinessHeader a:Id="id-E5f1ed32aab8f4578adeee5debd851a62" xmlns:h="urn:us:gov:treasury:irs:msg:acabusinessheader" xmlns:a="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns="urn:us:gov:treasury:irs:msg:acabusinessheader">
            <UniqueTransmissionId xmlns="urn:us:gov:treasury:irs:ext:aca:air:7.0">51958882-c653-4eab-8dfb-287ecc555aaa:SYS12:[TCC]::T</UniqueTransmissionId>
            <Timestamp xmlns="urn:us:gov:treasury:irs:common">2016-05-18T14:51:05.8568594-07:00</Timestamp>
        </ACABusinessHeader>
    </s:Header>
    <s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <ACABulkRequestTransmitter xmlns="urn:us:gov:treasury:irs:msg:irsacabulkrequesttransmitter" version="1.0">
            <BulkExchangeFile xmlns="urn:us:gov:treasury:irs:common">
                <inc:Include href="cid:1094C_Request_BB0S4_20160518T215105716Z.xml" xmlns:inc="http://www.w3.org/2004/08/xop/include" />
            </BulkExchangeFile>
        </ACABulkRequestTransmitter>
    </s:Body>
</s:Envelope>

--MIME_Boundary
Content-Type: text/xml; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Id: <1094C_Request_[TCC]_20160518T215105716Z.xml>
Content-Disposition: attachment; name="1094C_Request_[TCC]_20160518T215105716Z.xml"

[PrettyPrintFormDataXml]
--MIME_boundary--

Answer 1

Don't know if it will resolve your issue, but nevertheless i give it a shot. Sometimes help comes from very unexpected sources :)

1. First of all timestamp fields are in a wrong format: one in businessheader should NOT contain milliseconds at all. I know it for a fact.
2. In security header timestamp only 3 digits are allowed to represent milliseconds.
3. Remove empty elements like "OriginalReceiptId" from ACATransmitterManifestReqDtl element: they don't like those.
4. I hope you are providing them with proper software id, because you have it empty in the payload, but I am sure they would love to have it, imho.:)

5. And I think the message you've got in the response also have something to do with Signature element. I think they want Signature element to have some prefix("ds" preferably, I guess). But here I am not sure on 100%.

   You see, I am battling same battle as you. And my message security timestamp has prefix "u" and they do not complain about it. Though they didn't like binarysecuritytoken ever.:) I am struggling to generate signature to the IRS liking. WCF is very secretive and does not allow easy prefix changing on soap envelope or allow to choose CanonicalizationMethod algorithm for a signature.

UPDATE: Been able to successfully send request to the service. Tell you at once: prefixes are unimportant. What was important: CorrectedInd tag must be present in Form1095BUpstreamDetail and attributes recordType="String" lineNum="0" also must be present.

UPDATE2: Another thing that I've changed I've placed ACABusinessHeader before ManifestDtl. Here are my settings: I am using WCF as carrier and SignedXml to generate signature. Also I am using custom gZip encoder(for obvious reasons0 and custom MtomEncoder to read response from service(yes, yes it's MTOMed:)) can you believe those pokemons?!?!?) and that's not all: they send response as multipart document with only 1 part!:)) I had to adjust my encoder to handle that. And voilà, service started to behave. Hope it might help.

UPDATE3 First of all make sure data in attachment file correspond to the test scenario you are using as guinea pig. I, probably, sound like a broken record, but that's REALLY important. Now I'll cut the stuff and present what I have. It's a bit crude, but it does the trick.:)

1.Here is config file portion:
1.1.Make sure system.serviceModel element contains following portion:

<extensions>
  <bindingElementExtensions>
    <add name="gzipMessageEncoding" type="<namespaceWhereEncoderLives>.GZipMessageEncodingElement, GZipEncoder, Version=4.0.0.0, Culture=neutral, PublicKeyToken=null" />
  </bindingElementExtensions>
</extensions>  

1.2. Make sure binding element contains this:

  <customBinding>
    <binding name="BulkRequestTransmitterBinding">
      <gzipMessageEncoding innerMessageEncoding="textMessageEncoding" />
      <httpsTransport />
    </binding>
  </customBinding>

1.3. Change binding of BulkRequestTransmitterPort endpoit under client element to "customBinding"(and change binding name to the name of the custom binding as well) and make sure it contains following portion:

    <identity>
      <dns value="domain from cert" />
    </identity>

Also client element should contain following portion:

  <metadata>
    <policyImporters>
      <extension type="NamespaceToToTheLocationOf.GZipMessageEncodingBindingElementImporter, GZipMessageEncoder, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
    </policyImporters>
  </metadata>

2. GZip encoder you could get from following link: https://msdn.microsoft.com/en-us/library/cc138373(v=vs.90).aspx Just download WCF example and dully move whole GZipMessageEncoder project under your project.

3. Get MTOMEncoder(which I renamed from SwaEncoder for clarity reasons) from this link: Soap-with-Attachments Move following classes into GZipMessageEncoder project:
   MimeContent, MimeParser, MimePart, MTOMEncoder

4. Modify GZipMessageEncoder class like this:
   4.1. Add following code at the beginning of the class:

      //------------------- MTOM related stuff. Begin. ---------------------
       const string ATTCHMNT_PROP = "attachment_file_content";
       const string ATTCHMNT_CONTENT_ID = "Here goes content id";
   
       private string _ContentType;
       private string _MediaType;
   
       protected MimeContent _MyContent;
       protected MimePart _SoapMimeContent;
       protected MimePart _AttachmentMimeContent;
       protected GZipMessageEncoderFactory _Factory;
       protected MimeParser _MimeParser;
       private void SetupMTOM(GZipMessageEncoderFactory factory)
       {
           //
           _ContentType = "multipart/related";
           _MediaType = _ContentType;
   
           //
           // Create owned objects
           //
           _Factory = factory;
           _MimeParser = new MimeParser();
   
           //
           // Create object for the mime content message
           // 
           _SoapMimeContent = new MimePart()
           {
               ContentTypeStart = "application/xop+xml",
               ContentType = "text/xml",
               ContentId = "Here goes envelope MIME id from HTTP Content-Type header",   // TODO: make content id dynamic or configurable?
               CharSet = "UTF-8",                                  // TODO: make charset configurable?
               TransferEncoding = "8bit"                         // TODO: make transfer-encoding configurable?
           };
           _AttachmentMimeContent = new MimePart()
           {
               ContentType = "application/xml",                    // TODO: AttachmentMimeContent.ContentType configurable?
               ContentId = ATTCHMNT_CONTENT_ID,                    // TODO: AttachmentMimeContent.ContentId configurable/dynamic?
               TransferEncoding = "7bit"                         // TODO: AttachmentMimeContent.TransferEncoding dynamic/configurable?
           };
           _MyContent = new MimeContent()
           {
               Boundary = "here goes boundary id"  // TODO: MimeContent.Boundary configurable/dynamic?
          };
           _MyContent.Parts.Add(_SoapMimeContent);
           _MyContent.Parts.Add(_AttachmentMimeContent);
           _MyContent.SetAsStartPart(_SoapMimeContent);
       }
       //------------------- MTOM related stuff. End. ----------------------
   

4.2. Modify Method WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset) like this:

public override ArraySegment<byte> WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset)
        {
            ArraySegment<byte> buffer = innerEncoder.WriteMessage(message, maxMessageSize, bufferManager, 0);
            var requestSOAPEnvelopeXml = System.Text.Encoding.UTF8.GetString(buffer.Array);

            //Here you create Security node and sign the request. For ex:
            requestSOAPEnvelopeXml = SigngEnvelope(requestSOAPEnvelopeXml);
            //Here you are getting 1094\1095 forms xml payload.
            string fileContent = GetAttachmentFileContent();

            //Here comes the MTOMing...
            _SoapMimeContent.Content = System.Text.Encoding.UTF8.GetBytes(requestSOAPEnvelopeXml);
            _AttachmentMimeContent.Content = System.Text.Encoding.UTF8.GetBytes(fileContent);

            _MyContent.Parts.Where(m=> m.ContentId!=null && m.ContentId.Equals(ATTCHMNT_CONTENT_ID)).Single().ContentDisposition = GetFileName(envelope);
            // Now create the message content for the stream
            byte[] MimeContentBytes = _MimeParser.SerializeMimeContent(_MyContent);
            int MimeContentLength = MimeContentBytes.Length;

            // Write the mime content into the section of the buffer passed into the method
            byte[] TargetBuffer = bufferManager.TakeBuffer(MimeContentLength + messageOffset);
            Array.Copy(MimeContentBytes, 0, TargetBuffer, messageOffset, MimeContentLength);

            // Return the segment of the buffer to the framework
            return CompressBuffer(new ArraySegment<byte>(TargetBuffer, messageOffset, MimeContentLength), bufferManager, messageOffset);                
        }

4.3. Override couple more methods like this:

public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
        {
            ArraySegment<byte> decompressedBuffer = DecompressBuffer(buffer, bufferManager);

            MtomEncoder mtomEncoder = new MtomEncoder(innerEncoder, _Factory);
            Message returnMessage = mtomEncoder.ReadMessage(buffer, bufferManager, contentType);
            returnMessage.Properties.Encoder = mtomEncoder;

            return returnMessage;
        }

        public override bool IsContentTypeSupported(string contentType)
        {
            return true;
        }

4.4. Make sure GZipMessage constructor looks like this:

        internal GZipMessageEncoder(MessageEncoder messageEncoder, GZipMessageEncoderFactory factory)
            : base()
        {
            if (messageEncoder == null)
                throw new ArgumentNullException("messageEncoder", "A valid message encoder must be passed to the GZipEncoder");
            innerEncoder = messageEncoder;

            SetupMTOM(factory);
        }

5. Make sure GZipMessageEncodingBindingElement class has following method:

    public override void ApplyConfiguration(BindingElement bindingElement)
    {
        GZipMessageEncodingBindingElement binding = (GZipMessageEncodingBindingElement)bindingElement;
        PropertyInformationCollection propertyInfo = this.ElementInformation.Properties;
        if (propertyInfo["innerMessageEncoding"].ValueOrigin != PropertyValueOrigin.Default)
        {
            switch (this.InnerMessageEncoding)
            {
                case "textMessageEncoding":
                    binding.InnerMessageEncodingBindingElement = 
                        new TextMessageEncodingBindingElement(MessageVersion.Soap11, Encoding.UTF8);
                    break;
                case "binaryMessageEncoding":
                    binding.InnerMessageEncodingBindingElement = new BinaryMessageEncodingBindingElement();
                    break;
            }
        }
    }

6. Modify MTOMEncoder class. Make sure that following method looks like this:

   public override Message ReadMessage(System.IO.Stream stream, int maxSizeOfHeaders, string contentType)
   {
       VerifyOperationContext();
   
       if (contentType.ToLower().StartsWith("multipart/related"))
       {
           byte[] ContentBytes = new byte[stream.Length];
           stream.Read(ContentBytes, 0, ContentBytes.Length);
           MimeContent Content = _MimeParser.DeserializeMimeContent(contentType, ContentBytes);
   
           if (Content.Parts.Count >= 1)
           {
               MemoryStream ms = new MemoryStream(Content.Parts[0].Content);
               //At least for now IRS is sending SOAP envelope as 1st part(and only part(sic!) of MULTIpart response) as xml. 
               Message Msg = ReadMessage(ms, int.MaxValue, "text/xml");//Content.Parts[0].ContentType);
   
               if( Content.Parts.Count>1 )
                   Msg.Properties.Add(ATTCHMNT_PROP, Content.Parts[1].Content);
   
               return Msg;
           }
           else
           {
               throw new ApplicationException("Invalid mime message sent! Soap with attachments makes sense, only, with at least 2 mime message content parts!");
           }
       }
       else if (contentType.ToLower().StartsWith("text/xml"))
       {
           XmlReader Reader = XmlReader.Create(stream);
           return Message.CreateMessage(Reader, maxSizeOfHeaders, MessageVersion);
       }
       else
       {
           throw new ApplicationException(
               string.Format(
                   "Invalid content type for reading message: {0}! Supported content types are multipart/related and text/xml!",
                   contentType));
       }
   }
   

7. GZipMessageEncoderFactory class constructor should look like this:

      public GZipMessageEncoderFactory(MessageEncoderFactory messageEncoderFactory)
   {
       if (messageEncoderFactory == null)
           throw new ArgumentNullException("messageEncoderFactory", "A valid message encoder factory must be passed to the GZipEncoder");
       encoder = new GZipMessageEncoder(messageEncoderFactory.Encoder, this);
   }
   

8. This is how I call the service:

      var requestClient = new BulkRequestTransmitterPortTypeClient("BulkRequestTransmitterPort");
   
           requestClient.Endpoint.Contract.ProtectionLevel = System.Net.Security.ProtectionLevel.None;
    #if DEBUG
           var vs = requestClient.Endpoint.Behaviors.Where((i) => i.GetType().Namespace.Contains("VisualStudio"));
           if( vs!=null )
            requestClient.Endpoint.Behaviors.Remove((System.ServiceModel.Description.IEndpointBehavior)vs.Single());
   #endif                
      using (var scope = new OperationContextScope(requestClient.InnerChannel))
           {
                //Adding proper HTTP Header to an outgoing requqest.
               HttpRequestMessageProperty requestMessage = new HttpRequestMessageProperty();
   
               requestMessage.Headers["Content-Encoding"] = "gzip";
               requestMessage.Headers["Content-Type"] = @"multipart/related; type=""application/xop+xml"";start=""<Here goes envelope boundary id>"";start-info=""text/xml"";boundary=""here goes boundary id""";
               OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = requestMessage;
   
               response = requestClient.BulkRequestTransmitter(request.ACASecurityHeader,
                                                                   request.Security, ref request.ACABusinessHeader,
                                                                   request.ACATransmitterManifestReqDtl, 
                                                                   request.ACABulkRequestTransmitter);
           }
   

9. Modify Mime Part:

9.1. Add new method:

    public void GetHeader(StringBuilder Builder)
    {
        if (string.IsNullOrEmpty(ContentId) && string.IsNullOrEmpty(ContentType) && string.IsNullOrEmpty(TransferEncoding))
            return;

        if (!string.IsNullOrEmpty(ContentTypeStart))
        {
            Builder.Append(string.Format("Content-Type: {0}", ContentTypeStart));
            Builder.Append(string.Format("; type=\"{0}\"", ContentType));
        }
        else
            Builder.Append(string.Format("Content-Type: {0}", ContentType));

        if (!string.IsNullOrEmpty(CharSet)) Builder.Append(string.Format("; charset={0}", CharSet));
        Builder.Append(new char[] { '\r', '\n' });
        Builder.Append(string.Format("Content-Transfer-Encoding: {0}", TransferEncoding));
        Builder.Append(new char[] { '\r', '\n' });
        Builder.Append(string.Format("Content-Id: {0}", ContentId));
        Builder.Append(new char[] { '\r', '\n' });
        if (!string.IsNullOrEmpty(ContentDisposition))
            Builder.Append(string.Format("Content-Disposition: attachment; filename=\"{0}\"", ContentDisposition));
    }

9.2. Add property:

   public string ContentDisposition { get; set; }

10. Modify MimeParser SerializeMimeContent() method: replace this block of code:

           Builder.Append(string.Format("Content-Type: {0}", item.ContentType));
            if (!string.IsNullOrEmpty(item.CharSet)) Builder.Append(string.Format("; charset={0}", item.CharSet));
            Builder.Append(new char[] { '\r', '\n' });
            Builder.Append(string.Format("Content-Transfer-Encoding: {0}", item.TransferEncoding));
            Builder.Append(new char[] { '\r', '\n' });
            Builder.Append(string.Format("Content-Id: {0}", item.ContentId));
    

with this:

item.GetHeader(Builder);

And that's should be it! Kick off your shoes and dig the blues!:)))

Answer 2

First off, a quick disclaimer. This answer was made possible by the great stuff provided by fatherOfWine, Russ, and Bon across this and other SO questions. All I really did was combine a bunch of stuff from them them and hack through the issues I still had until it worked. More importantly, the code provided here is BAD and should probably not be used as-is. I plan on cleaning this up quite a bit now that I know what works, and I'd recommend anyone making use of it to do the same. A big thing that will likely jump out to anyone looking at this is the plethora of static variables I used as a quick hack to get to things all through the pipeline. Seriously, don't use this as-is in production, it is the product of many hours of just throwing things at the wall until something stuck, but it should provide a good starting point to get something better going.

---

There's too much code to really include it all here, so I'll just go through some highlights and general discoveries then include a link to the VS solution.

1. Make sure you have your TCC and various other IDs setup already, that you've purchased the right kind of certificate (Page 41 of this doc) and that you've registered the cert properly (see this doc)
2. I found that removing all the CR-LFs in the soap envelope was necessary to get the message to be accepted. With them in there I would gets faults on some elements of "unexpected child elements" or something like that.
3. The documentation contradicts itself in several place (see pages 74 and 84 and look at what they say the BulkExchangeFile element should contain for an example) and the wsdl/xsds are just straight up wrong as well. Maybe I just had old ones somehow, but I had to make changes and try things until I found what the service on their side would actually accept.
4. It is very important that you add the keyinfo to the signedxml section properly, that all of your references there are built right and include the proper InclusiveNamespaces lists, and that once you call ComputeSignature the only change you make to your envelope is to add the signature element to it.
5. Speaking of the signature element, if it appears after the timestamp element inside the security element the IRS system will return a fault. It has to be first.
6. Because the namespace prefixes were so important when it came to generating the signature references, I went the route of building the envelope xml by hand so I could be certain that everything matched up exactly with what they wanted. Even then, there were several elements whose prefixes I had to change as I tested because what the XSD or some page in the docs said it should be was not what their service actually wanted. Luckily the faults returned by the service actually provided some help by indicating which namespace it was expecting a value from.

7. Outside of getting all the gzip and MTOM stuff setup (again, thanks a million to fatherOfWine for that help) the bulk of what finally worked for me is done in single general-use class (which I cleverly called "General"). Again, this is bad code and was the product of just needing to get something (anything!) to work properly. I'll go ahead and include it here in the answer though in case it provides a quick "ah ha!" to anyone else working this problem.

   using System;
   using System.IO;
   using System.Net;
   using System.Security.Cryptography.X509Certificates;
   using System.Security.Cryptography.Xml;
   using System.ServiceModel;
   using System.ServiceModel.Channels;
   using System.Text;
   using System.Xml;
   using IrsAcaClient.ACABulkRequestTransmitterService;
   
   namespace IrsAcaClient
   {
   public class General
   {
       /*****************************************************
        * 
        * What I'm doing here (with static vars) is VERY BAD but this whole thing is just a dirty hack for now.
        * Hopefully I can clean this up later.
        * - JRS 2016-05-10
        * 
        *****************************************************/
       public const string SecurityTimestampStringFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffZ";
   
       public const string EnvelopeContentID = "<rootpart>";
   
       public static string AttachmentFilePath;
   
       public static string AttachmentFileName { get { return Path.GetFileName(General.AttachmentFilePath); } }
       public static string AttachmentContentID {get { return string.Format("<{0}>", General.AttachmentFileName); }}
   
       public const string MIMEBoundary = "MIME_boundary";
   
       public static string TCCode;
   
       public static Guid TransmissionGuid;
   
       public static string UniqueTransmissionId
       {
           get { return string.Format("{0}:SYS12:{1}::T", TransmissionGuid, TCCode); }
       }
   
       public static string SecurityTimeStampWsuId;
       public static string ManifestWsuId;
       public static string BusinessHeaderWsuId;
       public static string SignatureWsuId;
   
       public static string CertificatePath;
       public static string CertificatePassword;
   
       public static DateTime SecurityTimestampUTC;
   
       private static string _replacementSoapEnvelope;
   
       public static string ReplacementSoapEnvelope{get { return _replacementSoapEnvelope; }}
   
       private static void GenerateReference(string elementID, string inclusivePrefixList, SignedXmlWithId xSigned)
       {
           var reference = new Reference()
           {
               Uri = "#" + elementID
           };
   
           XmlDsigExcC14NTransform env = new XmlDsigExcC14NTransform();
           env.InclusiveNamespacesPrefixList = inclusivePrefixList;
           reference.AddTransform(env);
   
           xSigned.AddReference(reference);
       }
   
       public static string GetAttachmentFileContent()
       {
           //probably not ideal
           return File.ReadAllText(AttachmentFilePath);
       }
   
       public static string GetFileName()
       {
           //TODO: this may need to be tweaked slightly from the real filename
           return General.AttachmentFileName;
       }
   
       public static string GenerateWsuId(string prefix)
       {
           return string.Format("{0}-{1}", prefix, Guid.NewGuid().ToString().Replace("-", "").ToUpper());
       }
   
       internal static void GenerateReplacementSoapEnvelope(ACABulkRequestTransmitterService.SecurityHeaderType securityHeader, ACABulkRequestTransmitterService.ACABulkBusinessHeaderRequestType businessHeader, ACABulkRequestTransmitterService.ACATrnsmtManifestReqDtlType manifest, ACABulkRequestTransmitterService.ACABulkRequestTransmitterType bulkTrans)
       {
           //load the base envelope xml
           var doc = new XmlDocument();
           doc.PreserveWhitespace = false;
           doc.Load("BaseSoapEnvelope.xml");
   
           /* Need a bunch of namespaces defined
            * xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
            * xmlns:urn="urn:us:gov:treasury:irs:ext:aca:air:7.0"
            * xmlns:urn1="urn:us:gov:treasury:irs:common"
            * xmlns:urn2="urn:us:gov:treasury:irs:msg:acabusinessheader"
            * xmlns:urn3="urn:us:gov:treasury:irs:msg:irsacabulkrequesttransmitter"
            * xmlns:wsa="http://www.w3.org/2005/08/addressing"
            * xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
            * xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
            * xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
            * xmlns:xop="http://www.w3.org/2004/08/xop/include"
            */
           XmlNamespaceManager nsMgr = new XmlNamespaceManager(doc.NameTable);
           nsMgr.AddNamespace("soapenv", "http://schemas.xmlsoap.org/soap/envelope/");
           nsMgr.AddNamespace("urn", "urn:us:gov:treasury:irs:ext:aca:air:7.0");
           nsMgr.AddNamespace("urn1", "urn:us:gov:treasury:irs:common");
           nsMgr.AddNamespace("urn2", "urn:us:gov:treasury:irs:msg:acabusinessheader");
           nsMgr.AddNamespace("urn3", "urn:us:gov:treasury:irs:msg:irsacabulkrequesttransmitter");
           nsMgr.AddNamespace("wsa", "http://www.w3.org/2005/08/addressing");
           nsMgr.AddNamespace("wsse", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd");
           nsMgr.AddNamespace("wsu", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd");
           nsMgr.AddNamespace("ds", "http://www.w3.org/2000/09/xmldsig#");
           nsMgr.AddNamespace("xop","http://www.w3.org/2004/08/xop/include");
   
   
           //start replacing values in it
           //for securityHeader, should have the following
           /*
            * securityHeader.Signature.Id
            * securityHeader.Timestamp.Id
            * securityHeader.Timestamp.Created.Value
            * securityHeader.Timestamp.Expires.Value
            */
           //doc.SelectSingleNode("//wsse:Security/ds:Signature", nsMgr).Attributes["Id"].Value = securityHeader.Signature.Id;
           doc.SelectSingleNode("//wsse:Security/wsu:Timestamp", nsMgr).Attributes["wsu:Id"].Value = securityHeader.Timestamp.Id;
           doc.SelectSingleNode("//wsse:Security/wsu:Timestamp/wsu:Created", nsMgr).InnerText = securityHeader.Timestamp.Created.Value;
           doc.SelectSingleNode("//wsse:Security/wsu:Timestamp/wsu:Expires", nsMgr).InnerText = securityHeader.Timestamp.Expires.Value;
   
   
           //for businessHeader, should have the following
           /*
            * businessHeader.UniqueTransmissionId
            * businessHeader.Timestamp
            * businessHeader.Id 
            */
           doc.SelectSingleNode("//urn2:ACABusinessHeader", nsMgr).Attributes["wsu:Id"].Value = businessHeader.Id;
           doc.SelectSingleNode("//urn2:ACABusinessHeader/urn:UniqueTransmissionId", nsMgr).InnerText = businessHeader.UniqueTransmissionId;
           doc.SelectSingleNode("//urn2:ACABusinessHeader/urn1:Timestamp", nsMgr).InnerText = businessHeader.Timestamp.ToString("yyyy'-'MM'-'dd'T'HH':'mm':'ssZ");
   
   
           //for manifest, should have the following, some of which will need some conversions
           /*
            * manifest.Id
            * manifest.BinaryFormatCd - convert from enum
            * manifest.PaymentYr
            * manifest.PriorYearDataInd - convert from enum
            * manifest.EIN
            * manifest.TransmissionTypeCd - convert from enum
            * manifest.TestFileCd
            * manifest.TransmitterNameGrp.BusinessNameLine1Txt
            * manifest.CompanyInformationGrp.CompanyNm
            * manifest.CompanyInformationGrp.MailingAddressGrp.Item.AddressLine1Txt
            * manifest.CompanyInformationGrp.MailingAddressGrp.Item.CityNm
            * manifest.CompanyInformationGrp.MailingAddressGrp.Item.USStateCd - convert from enum
            * manifest.CompanyInformationGrp.MailingAddressGrp.Item.USZIPCd
            * manifest.CompanyInformationGrp.ContactNameGrp.PersonFirstNm
            * manifest.CompanyInformationGrp.ContactNameGrp.PersonLastNm
            * manifest.CompanyInformationGrp.ContactPhoneNum
            * manifest.VendorInformationGrp.VendorCd
            * manifest.VendorInformationGrp.ContactNameGrp.PersonFirstNm
            * manifest.VendorInformationGrp.ContactNameGrp.PersonLastNm
            * manifest.VendorInformationGrp.ContactPhoneNum
            * manifest.TotalPayeeRecordCnt
            * manifest.TotalPayerRecordCnt
            * manifest.SoftwareId
            * manifest.FormTypeCd - convert from enum
            * manifest.ChecksumAugmentationNum
            * manifest.AttachmentByteSizeNum
            * manifest.DocumentSystemFileNm
            */
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl", nsMgr).Attributes["wsu:Id"].Value = manifest.Id;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:PaymentYr", nsMgr).InnerText = manifest.PaymentYr;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:PriorYearDataInd", nsMgr).InnerText = manifest.PriorYearDataInd.GetXmlEnumAttributeValueFromEnum();
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn1:EIN", nsMgr).InnerText = manifest.EIN;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:TransmissionTypeCd", nsMgr).InnerText = manifest.TransmissionTypeCd.ToString();
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:TestFileCd", nsMgr).InnerText = manifest.TestFileCd;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:TransmitterNameGrp/urn:BusinessNameLine1Txt", nsMgr).InnerText = manifest.TransmitterNameGrp.BusinessNameLine1Txt;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:CompanyNm", nsMgr).InnerText = manifest.CompanyInformationGrp.CompanyNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:MailingAddressGrp/urn:USAddressGrp/urn:AddressLine1Txt", nsMgr).InnerText = ((USAddressGrpType)manifest.CompanyInformationGrp.MailingAddressGrp.Item).AddressLine1Txt;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:MailingAddressGrp/urn:USAddressGrp/urn1:CityNm", nsMgr).InnerText = ((USAddressGrpType)manifest.CompanyInformationGrp.MailingAddressGrp.Item).CityNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:MailingAddressGrp/urn:USAddressGrp/urn:USStateCd", nsMgr).InnerText = ((USAddressGrpType)manifest.CompanyInformationGrp.MailingAddressGrp.Item).USStateCd.ToString();
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:MailingAddressGrp/urn:USAddressGrp/urn1:USZIPCd", nsMgr).InnerText = ((USAddressGrpType)manifest.CompanyInformationGrp.MailingAddressGrp.Item).USZIPCd;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:ContactNameGrp/urn:PersonFirstNm", nsMgr).InnerText = manifest.CompanyInformationGrp.ContactNameGrp.PersonFirstNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:ContactNameGrp/urn:PersonLastNm", nsMgr).InnerText = manifest.CompanyInformationGrp.ContactNameGrp.PersonLastNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:CompanyInformationGrp/urn:ContactPhoneNum", nsMgr).InnerText = manifest.CompanyInformationGrp.ContactPhoneNum;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:VendorInformationGrp/urn:VendorCd", nsMgr).InnerText = manifest.VendorInformationGrp.VendorCd;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:VendorInformationGrp/urn:ContactNameGrp/urn:PersonFirstNm", nsMgr).InnerText = manifest.VendorInformationGrp.ContactNameGrp.PersonFirstNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:VendorInformationGrp/urn:ContactNameGrp/urn:PersonLastNm", nsMgr).InnerText = manifest.VendorInformationGrp.ContactNameGrp.PersonLastNm;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:VendorInformationGrp/urn:ContactPhoneNum", nsMgr).InnerText = manifest.VendorInformationGrp.ContactPhoneNum;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:TotalPayeeRecordCnt", nsMgr).InnerText = manifest.TotalPayeeRecordCnt;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:TotalPayerRecordCnt", nsMgr).InnerText = manifest.TotalPayerRecordCnt;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:SoftwareId", nsMgr).InnerText = manifest.SoftwareId;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:FormTypeCd", nsMgr).InnerText = manifest.FormTypeCd.GetXmlEnumAttributeValueFromEnum();
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn1:BinaryFormatCd", nsMgr).InnerText = manifest.BinaryFormatCd.GetXmlEnumAttributeValueFromEnum();
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn1:ChecksumAugmentationNum", nsMgr).InnerText = manifest.ChecksumAugmentationNum;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn1:AttachmentByteSizeNum", nsMgr).InnerText = manifest.AttachmentByteSizeNum;
           doc.SelectSingleNode("//urn:ACATransmitterManifestReqDtl/urn:DocumentSystemFileNm", nsMgr).InnerText = manifest.DocumentSystemFileNm;
   
   
           //for bulkTrans, should have the following
           /*
            * bulkTrans.BulkExchangeFile.Include.href
            */
           doc.SelectSingleNode("//urn3:ACABulkRequestTransmitter/urn1:BulkExchangeFile/xop:Include", nsMgr).Attributes["href"].Value = bulkTrans.BulkExchangeFile.Include.href;
   
   
           //now do some more security setup
           var cert = new X509Certificate2(CertificatePath, CertificatePassword, X509KeyStorageFlags.MachineKeySet);
   
           var exported = cert.Export(X509ContentType.Cert, CertificatePassword);
           var base64 = Convert.ToBase64String(exported);
   
           //now compute all the signing stuff
           var xSigned = new SignedXmlWithId(doc);
           xSigned.Signature.Id = securityHeader.Signature.Id;
   
           // Add the key to the SignedXml document.
           xSigned.SigningKey = cert.PrivateKey;
           xSigned.Signature.Id = SignatureWsuId;
           xSigned.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NWithCommentsTransformUrl;
   
           var keyInfo = new KeyInfo
           {
               Id = GenerateWsuId("KI")
           };
   
           //need to get the keyinfo into the signed xml stuff before we compute sigs, and because it is using some stuff that
           //doesn't appear to be supported out of the box we'll work around it by adding a node directly
           var sbKeyInfo = new StringBuilder();
           sbKeyInfo.Append("<root xmlns:wsse=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd\" xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" xmlns:ds=\"http://www.w3.org/2000/09/xmldsig#\">");
           sbKeyInfo.Append("<wsse:SecurityTokenReference wsu:Id=\"" + GenerateWsuId("STR") + "\">");
           sbKeyInfo.Append("<wsse:KeyIdentifier EncodingType=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary\" ValueType=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509v3\">" + base64.ToString());
           sbKeyInfo.Append("</wsse:KeyIdentifier>");
           sbKeyInfo.Append("</wsse:SecurityTokenReference>");
           sbKeyInfo.Append("</root>");
           XmlDocument tempDoc = new XmlDocument();
           tempDoc.LoadXml(sbKeyInfo.ToString());
   
           keyInfo.AddClause(new KeyInfoNode((XmlElement)tempDoc.FirstChild.FirstChild));
   
           xSigned.KeyInfo = keyInfo;
   
           GenerateReference(SecurityTimeStampWsuId, "wsse wsa soapenv urn urn1 urn2 urn3", xSigned);
           GenerateReference(BusinessHeaderWsuId, "wsa soapenv urn urn1 urn3", xSigned);
           GenerateReference(ManifestWsuId, "wsa soapenv urn1 urn2 urn3", xSigned);
   
           // Compute the Signature.
           xSigned.ComputeSignature();
   
           //signing stuff must come before the timestamp or the IRS service complains
           doc.SelectSingleNode("//wsse:Security", nsMgr).InsertBefore(xSigned.GetXml(), doc.SelectSingleNode("//wsse:Security", nsMgr).FirstChild);
   
           //
           _replacementSoapEnvelope = doc.OuterXml;
       }
   
       public static ACABulkRequestTransmitterResponseType Run(ACABulkRequestTransmitterService.SecurityHeaderType securityHeader, ACABulkRequestTransmitterService.ACABulkBusinessHeaderRequestType businessHeader, ACABulkRequestTransmitterService.ACATrnsmtManifestReqDtlType manifest, ACABulkRequestTransmitterService.ACABulkRequestTransmitterType bulkTrans)
       {
           //had some issues early on with the cert on the IRS server, this should probably be removed and retested without it
           ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, errors) => true;
           ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Ssl3 |
                                                  SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
   
           var acaSecurityHeader = new ACABulkRequestTransmitterService.TransmitterACASecurityHeaderType(); //leave this empty for transmitting via ISS-A2A
   
           var requestClient = new ACABulkRequestTransmitterService.BulkRequestTransmitterPortTypeClient("BulkRequestTransmitterPort");
   
           requestClient.Endpoint.Contract.ProtectionLevel = System.Net.Security.ProtectionLevel.None;
           //var vs = requestClient.Endpoint.Behaviors.Where((i) => i.GetType().Namespace.Contains("VisualStudio"));
           //if (vs != null)
           //    requestClient.Endpoint.Behaviors.Remove((System.ServiceModel.Description.IEndpointBehavior)vs.Single());
   
           //generate the real envelope we want
           GenerateReplacementSoapEnvelope(securityHeader, businessHeader, manifest, bulkTrans);
   
           using (var scope = new OperationContextScope(requestClient.InnerChannel))
           {
   
               //Adding proper HTTP Header to an outgoing requqest.
               HttpRequestMessageProperty requestMessage = new HttpRequestMessageProperty();
   
               requestMessage.Headers["Content-Encoding"] = "gzip";
               requestMessage.Headers["Content-Type"] = string.Format(@"multipart/related; type=""application/xop+xml"";start=""{0}"";start-info=""text/xml"";boundary=""{1}""", General.EnvelopeContentID, General.MIMEBoundary);
               OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = requestMessage;
   
               var response = requestClient.BulkRequestTransmitter(acaSecurityHeader,
                                                                   securityHeader,
                                                                   ref businessHeader,
                                                                   manifest,
                                                                   bulkTrans);
   
               //we got a response!  now do something with it
               return response;
   
           }
       }
   }
   

Here is the complete solution, just needs all of your own data supplied (including the complete attachment file with all the payee and payer records, which is outside the scope of this but should be pretty easy to generate). Also note that this is submission of forms only, not status checks. When I get that working I'll try to remember to return and update this answer (but if someone else already has it and wants to share, that'd be pretty rad as well).

---

Edit for Status Service

I've combined a cleaned up version of the classes generated from the wsdl and my own junk code to get messages through and process the responses. Note that this isn't 100% tested yet, needs sanity checks, etc. but like the previous stuff should at least help anyone else struggling with this mess. Usage here is pretty straightforward:

var statusResponse = StatusService.CheckStatus(receipt, tCCode, certificatePath, certificatePassword, "https://la.www4.irs.gov/airp/aca/a2a/1095BC_Status_Request_AATS2016");

And here is the full class (with bonus generated classes namespace):

See my second answer for the status service code

Answer 3

Seconds answer to include status service, rather than just another link that could disappear.

Here is the main class:

using System;
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml;
using System.Xml.Serialization;

namespace IrsAcaClient
{
    public class StatusService
    {
        private const string SecurityTimestampStringFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fffZ";


        public static ACABulkRequestStatusService.ACABulkRequestTransmitterStatusDetailResponseType CheckStatus(string receiptID, string tCCode, string certificatePath, string certificatePassword, string statusServiceUrl)
        {
            //go ahead and generate some of the ids and timestamps we'll need
            var securityTimeStampWsuId = GenerateWsuId("TS");
            var businessHeaderWsuId = GenerateWsuId("id");
            var detailRequestWsuId = GenerateWsuId("id");
            var signatureWsuId = GenerateWsuId("SIG");

            var securityTimestampUTC = DateTime.UtcNow;
            var securityTimestampCreated = securityTimestampUTC.ToString(SecurityTimestampStringFormat);
            var securityTimestampExpires = securityTimestampUTC.AddMinutes(10).ToString(SecurityTimestampStringFormat);

            //build the envelope
            //load the base envelope xml
            var doc = new XmlDocument();
            doc.PreserveWhitespace = false;
            doc.Load("BaseStatusRequestEnvelope.xml");

            /* Need a bunch of namespaces defined
             * xmlns:oas1="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
             * xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
             * xmlns:urn="urn:us:gov:treasury:irs:msg:irstransmitterstatusrequest"
             * xmlns:urn1="urn:us:gov:treasury:irs:ext:aca:air:7.0" 
             * xmlns:urn2="urn:us:gov:treasury:irs:common"
             * xmlns:urn3="urn:us:gov:treasury:irs:msg:acasecurityheader"
             * xmlns:wsa="http://www.w3.org/2005/08/addressing"
             * xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" 
             * xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
             * xmlns:ds="http://www.w3.org/2000/09/xmldsig#");
             */
            XmlNamespaceManager nsMgr = new XmlNamespaceManager(doc.NameTable);
            nsMgr.AddNamespace("soapenv", "http://schemas.xmlsoap.org/soap/envelope/");
            nsMgr.AddNamespace("urn", "urn:us:gov:treasury:irs:msg:irstransmitterstatusrequest");
            nsMgr.AddNamespace("urn1", "urn:us:gov:treasury:irs:ext:aca:air:7.0");
            nsMgr.AddNamespace("urn2", "urn:us:gov:treasury:irs:common");
            nsMgr.AddNamespace("urn3", "urn:us:gov:treasury:irs:msg:acasecurityheader");
            nsMgr.AddNamespace("wsa", "http://www.w3.org/2005/08/addressing");
            nsMgr.AddNamespace("wsse", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd");
            nsMgr.AddNamespace("wsu", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd");
            nsMgr.AddNamespace("oas1", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd");
            nsMgr.AddNamespace("ds", "http://www.w3.org/2000/09/xmldsig#");

            //start replacing values in it
            //for securityHeader, should have the following
            /*
             * securityHeader.Timestamp.Id
             * securityHeader.Timestamp.Created.Value
             * securityHeader.Timestamp.Expires.Value
             */
            doc.SelectSingleNode("//wsse:Security/wsu:Timestamp", nsMgr).Attributes["wsu:Id"].Value = securityTimeStampWsuId;
            doc.SelectSingleNode("//wsse:Security/wsu:Timestamp/wsu:Created", nsMgr).InnerText = securityTimestampCreated;
            doc.SelectSingleNode("//wsse:Security/wsu:Timestamp/wsu:Expires", nsMgr).InnerText = securityTimestampExpires;

            //for businessHeader, should have the following
            /*
             * businessHeader.UniqueTransmissionId
             * businessHeader.Timestamp
             * businessHeader.Id 
             */
            doc.SelectSingleNode("//urn:ACABusinessHeader", nsMgr).Attributes["wsu:Id"].Value = businessHeaderWsuId;
            doc.SelectSingleNode("//urn:ACABusinessHeader/urn1:UniqueTransmissionId", nsMgr).InnerText = GetUniqueTransmissionId(Guid.NewGuid(), tCCode);
            doc.SelectSingleNode("//urn:ACABusinessHeader/urn2:Timestamp", nsMgr).InnerText = securityTimestampUTC.ToString("yyyy'-'MM'-'dd'T'HH':'mm':'ssZ");

            //for ACABulkRequestTransmitterStatusDetailRequest, should have the following
            /*
             * ACABulkRequestTransmitterStatusDetailRequest.Id
             * ACABulkRequestTransmitterStatusDetailRequest.ACABulkReqTrnsmtStsReqGrpDtl.ReceiptId
             */
            doc.SelectSingleNode("//urn:ACABulkRequestTransmitterStatusDetailRequest", nsMgr).Attributes["wsu:Id"].Value = detailRequestWsuId;
            doc.SelectSingleNode("//urn:ACABulkRequestTransmitterStatusDetailRequest/urn1:ACABulkReqTrnsmtStsReqGrpDtl/urn2:ReceiptId", nsMgr).InnerText = receiptID;

            //now do some more security setup
            var cert = new X509Certificate2(certificatePath, certificatePassword, X509KeyStorageFlags.MachineKeySet);

            var exported = cert.Export(X509ContentType.Cert, certificatePassword);
            var base64 = Convert.ToBase64String(exported);

            //now compute all the signing stuff
            var xSigned = new SignedXmlWithId(doc);

            // Add the key to the SignedXml document.
            xSigned.SigningKey = cert.PrivateKey;
            xSigned.Signature.Id = signatureWsuId;
            xSigned.SignedInfo.CanonicalizationMethod = SignedXml.XmlDsigExcC14NWithCommentsTransformUrl;

            var keyInfo = new KeyInfo
            {
                Id = GenerateWsuId("KI")
            };

            //need to get the keyinfo into the signed xml stuff before we compute sigs, and because it is using some stuff that
            //doesn't appear to be supported out of the box we'll work around it by adding a node directly
            var sbKeyInfo = new StringBuilder();
            sbKeyInfo.Append("<root xmlns:wsse=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd\" xmlns:wsu=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd\" xmlns:ds=\"http://www.w3.org/2000/09/xmldsig#\">");
            sbKeyInfo.Append("<wsse:SecurityTokenReference wsu:Id=\"" + GenerateWsuId("STR") + "\">");
            sbKeyInfo.Append("<wsse:KeyIdentifier EncodingType=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary\" ValueType=\"http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509v3\">" + base64.ToString());
            sbKeyInfo.Append("</wsse:KeyIdentifier>");
            sbKeyInfo.Append("</wsse:SecurityTokenReference>");
            sbKeyInfo.Append("</root>");
            XmlDocument tempDoc = new XmlDocument();
            tempDoc.LoadXml(sbKeyInfo.ToString());

            keyInfo.AddClause(new KeyInfoNode((XmlElement)tempDoc.FirstChild.FirstChild));

            xSigned.KeyInfo = keyInfo;

            GenerateReference(securityTimeStampWsuId, "wsse wsa oas1 soapenv urn urn1 urn2 urn3", xSigned);
            GenerateReference(businessHeaderWsuId, "wsa oas1 soapenv urn1 urn2 urn3", xSigned);
            GenerateReference(detailRequestWsuId, "oas1 soapenv urn1 urn2 urn3", xSigned);

            // Compute the Signature.
            xSigned.ComputeSignature();

            //signing stuff must come before the timestamp or the IRS service complains
            doc.SelectSingleNode("//wsse:Security", nsMgr).InsertBefore(xSigned.GetXml(), doc.SelectSingleNode("//wsse:Security", nsMgr).FirstChild);

            //get the completed envelope
            var envelope = doc.OuterXml;

            //start the webrequest
            //get the request object
            var request = CreateWebRequest(statusServiceUrl);

            //get the request stream and then get a writer on it
            using (var stream = request.GetRequestStream())
            using (var gz = new GZipStream(stream, CompressionMode.Compress))
            using (var writer = new StreamWriter(gz))
            {
                //start by writing the soap envelope to the stream
                writer.WriteLine(envelope);
                writer.Close();
                stream.Close();
            }

            //get the response
            WebResponse response;

            //let an exception get thrown up the stack
            response = request.GetResponse();

            //get the response stream, get a reader on it, and read the response as text
            using (var responseStream = response.GetResponseStream())
            using (var reader = new StreamReader(responseStream, Encoding.UTF8))
            {
                var responseText = reader.ReadToEnd();

                //rip the one element (and children) we need out
                var match = Regex.Match(responseText, @"<(?'prefix'[\w\d]*):ACABulkRequestTransmitterStatusDetailResponse.*<\/\k<prefix>:ACABulkRequestTransmitterStatusDetailResponse>");

                return Deserialize<ACABulkRequestStatusService.ACABulkRequestTransmitterStatusDetailResponseType>(match.ToString());
            }
        }

        private static string GetUniqueTransmissionId(Guid transmissionGuid, string tCCode)
        {
            return string.Format("{0}:SYS12:{1}::T", transmissionGuid, tCCode);
        }

        private static string GenerateWsuId(string prefix)
        {
            return string.Format("{0}-{1}", prefix, Guid.NewGuid().ToString().Replace("-", "").ToUpper());
        }

        private static void GenerateReference(string elementID, string inclusivePrefixList, SignedXmlWithId xSigned)
        {
            var reference = new Reference()
            {
                Uri = "#" + elementID
            };

            XmlDsigExcC14NTransform env = new XmlDsigExcC14NTransform();
            env.InclusiveNamespacesPrefixList = inclusivePrefixList;
            reference.AddTransform(env);

            xSigned.AddReference(reference);
        }

        /// <summary>
        /// creates a webrequest object and prefills some required headers and such
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        private static HttpWebRequest CreateWebRequest(string url)
        {
            //setup a web request with all the headers and such that the service requires
            var webRequest = (HttpWebRequest)WebRequest.Create(url);

            webRequest.Method = "POST";
            webRequest.ProtocolVersion = HttpVersion.Version11;
            webRequest.Headers.Add(HttpRequestHeader.ContentEncoding, "gzip");
            webRequest.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip, deflate");
            webRequest.ContentType = "text/xml;charset=UTF-8";
            webRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
            webRequest.Headers.Add("SOAPAction", "RequestSubmissionStatusDetail");
            webRequest.KeepAlive = true;

            return webRequest;
        }

        /// <summary>
        /// deserializes the xml string into an object
        /// </summary>
        /// <param name="xmlString"></param>
        /// <returns></returns>
        public static T Deserialize<T>(string xmlString) where T : class
        {
            //if the string is empty, just return null
            if (xmlString.Length <= 0)
            {
                return null;
            }

            //create a serializer
            var serializer = new System.Xml.Serialization.XmlSerializer(typeof(T));
            T output;
            //create the reader that the serializer will read from, passing it the string
            using (var reader = new System.IO.StringReader(xmlString))
            {
                //rebuild the list object
                output = (T)serializer.Deserialize(reader);
            }
            //return the list
            return output;
        }
    }
}

Here is the relevant base xml:

<?xml version="1.0" encoding="utf-8" ?>
<soapenv:Envelope
xmlns:oas1="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:urn="urn:us:gov:treasury:irs:msg:irstransmitterstatusrequest"
xmlns:urn1="urn:us:gov:treasury:irs:ext:aca:air:7.0" xmlns:urn2="urn:us:gov:treasury:irs:common"
xmlns:urn3="urn:us:gov:treasury:irs:msg:acasecurityheader">
  <soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing">
    <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
      <wsu:Timestamp wsu:Id="XXXXXXXXXXXXXXXXXX">
        <wsu:Created>XXXXXXXXXXXXXXXXXX</wsu:Created>
        <wsu:Expires>XXXXXXXXXXXXXXXXXX</wsu:Expires>
      </wsu:Timestamp>
    </wsse:Security>
    <urn:ACABusinessHeader wsu:Id="XXXXXXXXXXXXXXXXXX" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
      <urn1:UniqueTransmissionId>
        XXXXXXXXXXXXXXXXXX
      </urn1:UniqueTransmissionId>
      <urn2:Timestamp>XXXXXXXXXXXXXXXXXX</urn2:Timestamp>
    </urn:ACABusinessHeader>
    <urn3:ACASecurityHeader />
    <wsa:Action>RequestSubmissionStatusDetail</wsa:Action>
  </soapenv:Header>
  <soapenv:Body>
    <urn:ACABulkRequestTransmitterStatusDetailRequest version="1.0" wsu:Id="XXXXXXXXXXXXXXXXXX" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
      <urn1:ACABulkReqTrnsmtStsReqGrpDtl>
        <urn2:ReceiptId>XXXXXXXXXXXXXXXXXX</urn2:ReceiptId>
      </urn1:ACABulkReqTrnsmtStsReqGrpDtl>
    </urn:ACABulkRequestTransmitterStatusDetailRequest>
  </soapenv:Body>
</soapenv:Envelope>

For this one, the main change I needed to make to the WSDL-generated classes was the following:

    [System.SerializableAttribute()]
    [XmlRoot("ACABulkRequestTransmitterStatusDetailResponse", Namespace = "urn:us:gov:treasury:irs:msg:irstransmitterstatusrequest")]
    public class ACABulkRequestTransmitterStatusDetailResponseType
    {
        private ACABulkRequestTransmitterResponseType aCABulkRequestTransmitterResponseField;
        private ACABulkReqTrnsmtStsRespGrpDtlType aCABulkReqTrnsmtStsRespGrpDtlField;
        private string versionField;
        public ACABulkRequestTransmitterStatusDetailResponseType()
        {
            this.versionField = "1.0";
        }
        [System.Xml.Serialization.XmlElementAttribute(Namespace = "urn:us:gov:treasury:irs:ext:aca:air:7.0", Order = 0)]
        public ACABulkRequestTransmitterResponseType ACABulkRequestTransmitterResponse
        {
            get
            {
                return this.aCABulkRequestTransmitterResponseField;
            }
            set
            {
                this.aCABulkRequestTransmitterResponseField = value;
            }
        }
        [System.Xml.Serialization.XmlElementAttribute(Namespace = "urn:us:gov:treasury:irs:ext:aca:air:7.0", Order = 1)]
        public ACABulkReqTrnsmtStsRespGrpDtlType ACABulkReqTrnsmtStsRespGrpDtl
        {
            get
            {
                return this.aCABulkReqTrnsmtStsRespGrpDtlField;
            }
            set
            {
                this.aCABulkReqTrnsmtStsRespGrpDtlField = value;
            }
        }
        [System.Xml.Serialization.XmlAttributeAttribute()]
        public string version
        {
            get
            {
                return this.versionField;
            }
            set
            {
                this.versionField = value;
            }
        }
    }

Answer 4

Adding the ds prefix is actually what is breaking this. The SignatureValue element contains the x509 hash of the serialized SignedInfo element (this is where having consistent whitespace matters).

By modifying the SignedInfo element, the authentication will fail when the IRS compares the SignatureValue hash you send against their computation of the SignedInfo hash using the certificate you uploaded and associated with the provided TCC.

Just remove your modification of the SignedInfo element and all should be good. It works for me.

Answer 5

This was an edit made to the above post, which added more information to jstill's post. Unfortunately, peer reviewers rejected it.

In addition to the changes jstill made to the Status' Reference.cs file, I also had to include the BulkExchangeFileType and IncludeFileType updates he made to the Submission's Reference.cs file in order to get the Deserializer method to function partially.

The Deserializer method will return the TransmissionStatusCd and the ReceiptId elements as expected, however, it will not populate the ErrorDataFile element properly.

Since, at this time, I am unable to get the ErrorDataFile object populated properly, I am not utilizing the ACABulkRequestTransmitterStatusDetailResponseType object to capture the response returned from the Status Web Service. Instead, I have chosen to read the ResponseStream into a string object and parse the (up to) two MIME parts of the response, and process those as necessary.

---

Additional changes to the Status' Reference.cs

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.34283")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "urn:us:gov:treasury:irs:common")]
public partial class BulkExchangeFileType : object, System.ComponentModel.INotifyPropertyChanged
{
    private IncludeType includeField;

    /// <remarks/>
    [System.Xml.Serialization.XmlElement(Order = 0, Namespace = "http://www.w3.org/2004/08/xop/include")]
    public IncludeType Include
    {
        get { return this.includeField; }
        set
        {
            this.includeField = value;
            this.RaisePropertyChanged("Include");
        }
    }

    public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(string propertyName)
    {
        System.ComponentModel.PropertyChangedEventHandler propertyChanged = this.PropertyChanged;
        if (propertyChanged != null)
        {
            propertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
        }
    }
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "4.0.30319.34283")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace = "http://www.w3.org/2004/08/xop/include")]
public partial class IncludeType : object, System.ComponentModel.INotifyPropertyChanged
{
    private System.Xml.XmlNode[] anyField;
    private string hrefField;

    /// <remarks/>
    [System.Xml.Serialization.XmlTextAttribute()]
    [System.Xml.Serialization.XmlAnyElementAttribute(Order = 0)]
    public System.Xml.XmlNode[] Any
    {
        get { return this.anyField; }
        set
        {
            this.anyField = value;
            this.RaisePropertyChanged("Any");
        }
    }

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute(DataType = "string")]
    public string href
    {
        get { return this.hrefField; }
        set
        {
            this.hrefField = value;
            this.RaisePropertyChanged("href");
        }
    } 

    public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(string propertyName)
    {
        System.ComponentModel.PropertyChangedEventHandler propertyChanged = this.PropertyChanged;
        if (propertyChanged != null)
        {
            propertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
        }
    }
}

Answer 6

For those running into the following error:

AIRMF3002 Rejected transmission - Unable to process your request because validation failure occurs in the Attachment Byte Size Number

It appears there is an issue on the IRS side with the size they are expecting (as per the Documentation) and the size they actually accept. Originally, I had the following code:

// Size in Bytes of File: This code returns the "Size" located on the File's Property Page.
// Result: TRANSMISSION REJECTED ON INCORRECT FILE SIZE!
manifestHeader.AttachmentByteSizeNum = new FileInfo(FormDataFilePath).Length.ToString();

I replaced the above code with the following, and the error I was receiving was resolved.

// Read the contents of the file, and retrieve the length of the content of the file itself..
// Result: TRANSMISSION WAS ACCEPTED USING THIS FILE SIZE.
manifestHeader.AttachmentByteSizeNum = File.ReadAllText(FormDataFilePath).Length.ToString();

It appears as though the Web Service is actually expecting the size of the file content and not the size of the actual file. The difference in size pertaining to the test scenarios was approximately 3 bytes. I assume that is because retreiving the size of the file adds some additional file-related information not belonging to the actual content.

I have notified the IRS about this issue regarding their documentation.