In the given case, I want to use a facelet with different ManagedBeans, so the regarding action-bean is given as an parameter:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html 
    xmlns="http://www.w3.org/1999/xhtml" 
    xmlns:ui="http://java.sun.com/jsf/facelets" 
    xmlns:h="http://java.sun.com/jsf/html" >
<h:body>
    <ui:include src="ratings.xhtml" >
      <ui:param name="createAction" value="#{myOneCreateAction}" />
      <ui:param name="ratings" value="#{context.ratings}" />
    </ui:include>
</h:body>
</html>
I'm giving the create action as parameter value="#{myOneCreateAction}".
Within that facelet is a component also being used several times on other pages - so I try to refactor it in a composite component.
<html xmlns="http://www.w3.org/1999/xhtml" 
  xmlns:ui="http://java.sun.com/jsf/facelets" 
  xmlns:h="http://java.sun.com/jsf/html" 
  xmlns:f="http://java.sun.com/jsf/core" 
  xmlns:io="http://java.sun.com/jsf/composite/inoutComponents">
<ui:composition>
    <rich:dataTable id="ratingTblId" 
    value="#{ratings}" 
    var="rating">
        <rich:column>
             <io:removeButton
                 id="removeButton"
                 actionMethod="#{createAction.removeRating}"
                 immediate="true"
                 render=":#{rich:clientId('ratingTblId')}" />
             <h:commandButton
                 id="removeButton2"
                 actionListener="#{createAction.removeRating}"
                 immediate="true" >                    
                    <f:ajax render="ratingTblId" />
              </h:commandButton>
        </rich:column>
</rich:dataTable>
</ui:composition>
</html>
See, how the method is given as actionMethod="#{createAction.removeRating}" to the component. This component itself looks like following:
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:cc="http://java.sun.com/jsf/composite">
    <!-- INTERFACE -->
    <cc:interface>
        <cc:attribute 
            name="actionMethod" 
            targets="remove" 
            method-signature="void f(javax.faces.event.ActionEvent)"/>
        <cc:attribute name="render" required="false" />
    </cc:interface>
    <!-- IMPLEMENTATION -->
    <cc:implementation> 
        <h:commandButton 
           id="remove"
           actionListener="#{cc.attrs.actionMethod}" 
           onclick="if (!confirm('Do you really?')) { return false; }">
           <f:ajax execute="@this" render="#{cc.attrs.render}" />
        </h:commandButton> 
    </cc:implementation>
</ui:composition>
and last but not least, the managed bean
Name("myOneCreateAction")
@Scope(ScopeType.CONVERSATION)
public class MyOneCreateAction {
   ...
   public void removeRating(ActionEvent ev) {
        // do something
   }
   ...
}
Surprisingly, while the removeButton2 correctly jumps into the right function, the composite components version returns a
javax.faces.event.AbortProcessingException: Target Unreachable, 
      identifier 'createAction' resolved to null
instead. Am using Mojarra JSF 2.1.26 with Seam 2.3.1.CR1. There are no nested composite components. When replacing the composite component parameter to #{myOneCreateAction.removeRating}, it works like expected.
Has anybody seen this before? Am I blind? Any work-arounds known... ? Thanks in advance!