In JBoss 6 M4 the JMXConnector defined in jmx-jboss-beans.xml (org.jboss.system.server.jmx.JMXConnector) does not allow to use SSL although this can be done with standard Java JMX over RMI classes. The SocketFactories are hard coded:
DefaultClientSocketFactory clientSocketFactory = new DefaultClientSocketFactory();
clientSocketFactory.setBindAddress(hostname);
DefaultSocketFactory serverSocketFactory = new DefaultSocketFactory();
serverSocketFactory.setBindAddress(hostname);
registry = LocateRegistry.createRegistry(rmiRegistryPort, clientSocketFactory, serverSocketFactory);
Since credentials and other sensitive data are sent over the wire, using SSL should be possible without writing your own JMXConnector.
Thanks, Harald