WSContext.getUserPrincipal() returns null for password digest authentication

Question

In my WebService I need to log the caller's id, but wsContext.getUserPrincipal() returns null even though the user was authenticated using WS-Security with password authentication. According to the JavaDocs for JAX-WS 2.1 WSContext.getUserPrincipal() should only return null if the user has not been authenticated.

Do I have to do something in the security handler to set the user principal into the WSContext? The docs seem to indicate that it is done automatically.

I'm using the metro 1.1 stack (1.1.5 I think) with jax-ws 2.1.3 stack on Tomcat.