Actually JBP uses no cache, the HashtableCacheProvider is just here to prevent an error if it would not be present.
The setting for 2.2 will change and uses EHCache as default cache as JBoss Portal will do more database related operations (like portal object persistence).
So if I want to use the JBoss tree cache provider with my implementation of the portal, what is the best way to implement this change? I want to get the most upgradability from my solution. Should I subclass the SessionFactoryBinder MBean and replace the offending line in startService(), or is there another more preferred method?