I have read many posts, blogs and pieces of documentation on the illusive subject "soap headers in flex". I have seen many frustrated developers asking for more information on how to add, for example, complex-type SOAP-header information. I also found that I needed to be able to put complex-type headers into my SOAP requests. This for the simple reason that I use wsse security in my webservices.
I have found a relative solution that solves my problems.