My Jawbone Generation No. 2 device, bluetooth head set, works only when I manually slide the Skype volume controler located on the 'Audio Settings' menue 'Options' - back and forth. Otherwise, both the Microphone and Speaker on the blue tooth device time out. No such problem with the first generation Jawbone device on either Vista or Windows 7.0 (Beta) O/S.
This appears to be a device driver issue:
Bluetooth Hands-free Audio Device
File version: 6.1.7000.0 (winmain_win7beta.081212-1400)