Those are all the system properties I can think of, they look like they are set correctly. The JMX plugin isn't auto-discovering the remote JMX server running inside JBoss - check firewalls, and that the agent can ping the IP that the JBossAS JMX Server bound its remote listener to (that's probably not it - usually it will default to "localhost" so that shouldn't be a problem, but I've seen firewalls do things that I never expect so, I bring it up just in case)
You can read this blog - perhaps it has some hints for you to try? This does NOT involve remoting JBoss's JMX Server - it just talks about generic remote JMX Servers, so it may not be too helpful, but you never know:
I was expecting agent can discover the jmx server automatically. I started to see the jvm after manually adding jmx server to inventory.
Thanks for help.