What amkes you think that is it a JBoss Portal Server bug ? Any URL ?
i got the same problem for many weeks !
take a look at jacote's message.
i think this problem is not solved.
After lot of work, I was found source of problem.
For store per-applicaton instances of configurable JSF classes ( Factories etc ) JSF use context class loader ( Thread.currentThread().getContextClassLoader() ) as key in static Map ( as far as many web libraries ).
With installed portal service, Jboss call init() method of filter with different context, and incorrect classloader !
As a result, JSF do not have acces to configured instances, and filter methods don't show application classes.
In lates release ajax4jsf, most of initialization work moved from init() method, and applications can work with Jboss portal service.
P.S. For properly work inside portal, we need more changes - this feature targetted to ajax4jsf 1.1 release.