Primer: Passing the SOAP Headers
How to pass SOAP headers to and from backend service in parallel calls. In an ideal world, a split-join service would pass any SOAP headers to the backend service and back without any effort. In the real world, the headers inevitably get lost along the way. There is apparently a predefined set of conditions that both the WSDL and the request must comply with for the headers to travel through safely; however, most services I see in the real world simply do not comply.