The jmx remoting component within JBoss 3.2.5 was a proprietary predecessor to the JMX Remoting spec (JSR-160). Since the spec came out, the effort for jmx remoting implementation (targeted for JBoss 5.0 as you mentioned) has been based on this spec. The MBeanTracker (and most of the other classes in the older releases) are no longer being developed or supported.
However, for the moment, the code for this still exists within the 4.0 branch. It is not part of the default build or distribution though. It might be possible to get what you need from there.