Good articles on how to add SOAP headers when you are using CXF and the headers are complex XML rather than simple strings.
http://stackoverflow.com/questions/3807922/with-cxf-actually-groovyws-how-do-i-generate-a-soap-header-with-one-child-nod
http://blog.bemoko.com/2010/08/12/groovyws-cxf-and-net-webservices-with-an-authheader-pain/