I've narrowed it down a bit. When entering the IP address to go to the JBoss Console, all access requests are logged. It must be because of the virtual host created in jboss-web.xml.
I've looked at the Tomcat Access Log Valve documentation - not a word on virtual hosts or anything else that may help.
Found the solution in the Wiki pages virtual host how-to. Basically, it consists of a few more entries in server.xml.