Accessing the WS signing certificate from inside a JAX-WS webservice

When I have set up the webservice as in the previous post to require signatures, it's very normal that I would like to know who signed the certificate. Also I probably want to access the credentials of the signature, in this case the certificate.

How do I retrieve the signature certificate of a WS-security signed SOAP message?

I could not find any good post describing this on the Internet...

Well here it is now:

 @Resource
 private WebServiceContext wsContext; 

<snip>

     MessageContext mctx = wsContext.getMessageContext(); 
     Subject s = (Subject)mctx.get("CLIENT_SUBJECT");
     Set cs = s.getPublicCredentials();
     for (Iterator iterator = cs.iterator(); iterator.hasNext();) {
   Object object = (Object) iterator.next();
   System.out.println("Object: "+object.getClass().getName());
   if (object instanceof X509Certificate) {
    System.out.println("Found a certificate");
    X509Certificate cert = (X509Certificate) object;
    System.out.println(cert.toString());
   }
  }
     if (s != null) {
      Set ps = s.getPrincipals();
      for (Iterator iterator = ps.iterator(); iterator.hasNext();) {
       Principal principal = (Principal) iterator.next();
       if (principal instanceof X500Principal) {
        X500Principal xp = (X500Principal) principal;
    System.out.println(xp.getName());
       }
      }
     }

<snip>