Apparently most Motorola devices support 2 Bluetooth Stacks: Microsoft and StoneStreet. To switch which stack to use you would have to make some changes in the registry and restart the device.
0 = Microsoft Stack
1 = StoneStreet One Stack
The StoneStreet One Stack is supported in all devices except the ES400 and MC65. For the Microsoft stack, any device running Windows Mobile 6.1, Windows Mobile 6.5.x and Windows CE 6.0
Motorola recommendeds using the Microsoft stack for new development and I strongly agree with Motorola on this!