Not sure that'll work... I have the nav, and it doesn't seem to support anything except for phone audio via bt. Not that I've tried to fight it. But the audio menus don't have anything for bt source.
if it was me and I _REALLY_ wanted stereo bt, the nav comes with a/v (yes video.. but it only works after you defeat the 'in park' interlocks or aren't moving) and ipod inputs. The a/v's are rca, the audio section works all the time.
buy this, and pair with it, and usb charge it from the plug that's in there. And buy a stereo mini plug to rca cable.
If you don't have the nav, I *think* that the one that comes with the bberry adaptor will work.
Amazon.com: Blackberry 60-1699-01-RM Blackberry Bluetooth Stereo Gateway: Cell Phones & Service