I can only add my voice to this question. I can't answer it. I too am experiencing the problem. The Firewall performs Network Address Translation between the external IP address and the internal (LAN) IP address of the box that JBoss is running on. JBoss passes back the internal IP address to the client (NAT can't translate it as it is in the payload of the response packets rather than in the header). The client obviously can't access this internal address.
ANy insights welcome.