Look up the Widcomm BT stack here on Aximsite, that fixes WM5's crippled BT stack.
Yes, you heard me right, WM5 BT is a downgrade from 2003. Dell removed the Widcomm stack.

(My personal opinion: Dell wanted to remove support for some BT stuff, such as headsets, so we poor WM5 users would be forced to use Dell branded accessories.)