Exactly the same problem. Took the car and the Ipod to my dealer. Mechanic confirmed the problem as he tested the car with the 5th Gen Ipod and it worked fine. He sent in the bug to BMW. We just have to wait for BMW to make a software fix.

I would suggest that you do the same, take it to your dealer and let them confirm the bug and report it. The more of us who do this the more chance BMW will listen and fix it.