Well, it's a pity that Ajax4JSF cannot handle this really basic problem (which has nothing to do with authentication).
So, I had to implement a JSF filter to redirect each time the request session is new. But again, that's NOT the way I expected it to work... :(
I did created JIRA issue for a this problem.
Also, I have a some problems with commons-digetester, wich have a strange dependencies from a JAXP implementations ( especially, it work wrong with Oracle OC4J server ).
Sorry, last message have been submitted into different thread...