jms message ack problem in transaction

[mickey hendrix]

Hi,
I have a problem with th ack of jms message in relation of the cmp transaction attribute.
I have an MDB with CMP transaction attribute set to Required that receive a message from a queue 1 and send a message on a queue 2.On this Queue 2 there as another MDB with transaction attribute set to Required to.
The problem is that the second MDB doesn't receive the message from the first MDB.
But If I set the transaction attribute of the first MDB to NotSupported the message arrives to the second MDB.
Why?Where is my mistake?
I work on Weblogic Server 8.1 sp6
thanks for help