Thanks for the tip!
Issue:
I have set A.Slave on the BLC, and the BeoSound 9000 turns on and off automatically as expected.
However:
When I press a button on the BeoSound 9000, the TV with the connected surround speakers does not turn on automatically.
Question about multiroom setup:
If I connect the BeoLab 5000 and the IR eye in another room directly to the BLC, it should also work with A.Slave, right?