Can override built-in action on WSS4JOutInterceptor but seems impossible to add a new custom action on WSS4JOutInterceptor

CXF documentation at http://cxf.apache.org/docs/ws-security.html (#Custom Action)claims that you can configure WSS4JOutInterceptor to override a built-in action with a custom actions or add your own custom action.
Overriding built-in action works fine, but adding a new action does not. The current WSS4JOutInterceptor Java code
probably need modifications to allow adding own custom actions.