I read your article. From what I gathered I have deduced that you must have an element with a message context property..and this is possible only in propert schemas(right?) and can I have property schemas as a header schema? according to the file structure I posted above?
Pipelines can also promote fields. I just started working at a place where they use a lot of SOAP-Headers (not sure exactly what you mean by header). They have a custom pipeline that promotes various fields in the SOAP Header.