Treo Versions of Bluetooth may provide a clue...
Treo 650 BT 1.1 upgradable to 1.13
Treo 680 BT 1.2 (Not available yet in USA, but coming to Cingular soon)
Treo 700 BT 1.2
Treo 750 BT 1.2 (UMTS, can receive data and talk simultaneous)
BT 1.2 is said to be back compatible with 1.1
I had a meeting with a representative of Palm and was told the issue is more due to carrier issues, not BMW.
Completed Sept. 8, 2006
US Delivery November 3rd, 2006: 328xi sedan sparkling graphite, Black Dakota, sport, premium, sound, Navigation, Xenon