Hi!
If you want to use generated artifacts, then handlers is a way that you can use to add custom SOAP headers to outgoing messages both on the client and server side.
I suspect, though, that in order to be able to manipulate the SOAP message in the handler code, you will have to use SAAJ or some API that offers similar functionality.
For an example of how to implement a handler that does not add custom headers, see section 9.4 of my study notes. I am sorry, but as far as I recall, I don't have an example of a handler that adds custom headers.
Best wishes!