I have exactly the same problem.
It there a start up guide available for merging portlet and ajax4jsf?
Can you add your war to this thread? It will be much easier to try to deploy it.
For regular Ajax : see the samples provided with the portal (2.6.2).
For use of RichFaces : it is brand new... and still a few difficulties. It is just a question of time and the team work hard on it to solve things as fast as possible...
these jira allow you to see what's going on :
there is another jira, about a classcastexception in the jsf portlet bridge.
i can't get it know (jira server not responding)
but this jira is good: tells you the last solution, and how.
there is a example provided (war)
search in the jira...
this post too :
to build your code, you also have this (it is a demo, I have not yet looked at it, but planned to do...)
Building Rich Internet Applications with JBoss RichFaces :
hope it helps...