beemermania

I recently bought a 2005-E60. Ever since I bought it I am having issues with the bluetooth. My o2 Atom and BMW pair perfectly when I start the engine. Phone book is transfered, fine. But problem is when I try to make/recive a call from my steering the calls gets connected but I can't hear anything and even the other party can't hear anything. But if I dial the number from my phone, I can talk and hear from my BMW speakers. I am confused, would appreciate any help. Thanks.