check this link: http://oradbastuff.blogspot.com/2012/05/secureregisterlistener.html
also check the listener log, usually its here: $ORACLE_HOME/network/log/listener. log
or you can the command "lsnrctl stat" which will have one entry named "listener log file /..../etc"
I do have it working.
I do get the messages indicating that attempts to register are being blocked from the listener.log:
15-MAY-2014 00:00:50 * service_register_NSGR * 1194
TNS-01194: The listener command did not arrive in a secure transport
What I'd like to know is if there is a way to identify where those register attempts are coming from.
lsnrctl status does doesnt tell me that.