I have a use case where we want to add some additional code to the Java bean object generated by WsGen. The Sun JAXB schema compiler allows you to develop extensions to modify the AST of the beans before the code is generated. The extensions are activated via command line options to the schema compiler.
I've added a bindingOptions command line argument to WsGen that will let you pass though your own options to the JAXB schema compiler. Attached are patches to XFire 1.2.6 to enable this new option.