Can you post details of the error/stacktrace?
Can you post some sample code that we can look at to see how you've implemented this?
I do not know which Saint to pray ... I lost a loto of time and now I got this error.... despite guarantees of richfaces' team in this forum that the approach with selection could be followed well..
(As an aside, I'm pretty sure we didn't "guarantee" anything - guarantees are the stuff of SLA's and support contracts. OSS is done on a best effort basis.)