Thanks for the helpful suggestion. It helped me alot :DD
Now I know how to proceed and so I've tried these here and it works very well, due to your helpful suggestion:
@Resource
protected WebServiceContext wsContext;
MessageContext msgCtxt = wsContext.getMessageContext();
Object clientsubject= msgCtxt.get("CLIENT_SUBJECT");
String cs= clientsubject.toString();
int x= cs.indexOf("URIName:");
//and so on
Finally I get the extension of my certificate :D
[Message sent by forum member 'armerino']
http://forums.java.net/jive/thread.jspa?messageID=470259