if you have an entity which is reference in the client and a webservice like this
public class Post
{    
        public int ID {get; set;}
        string Data {get; set;}
}
 public class MyService: System.Web.Services.WebService
 {   
         [WebMethod]
         public int Write (Post post)
         { 
               //Do stuff
         }
 }
on the client in order to use the entity you to instantiate from the proxy class
   public void ClientMethod()
      {
         var post = new proxyclass.Post();
         //fill post
         new ProxyClass.Myservice().Write(post) 
       }
how can i use my domain entity to call the webservice?
 public void ClientMethod()
          {
             var post = new Post();
             //fill post
             new ProxyClass.Myservice().Write(post) 
           }