Dell GPS works even better in WM5, I must say. All you need to do is

1. turn on BT. set up a partnership with the receiver. Remember to use "secure" connection and the passkey is 2003
2. add one outgoing serial port and one incoming serial port
3. go to "GPS" settings. choose the incoming port you just set up in the "Progrms" tab; choose the outgoing port you just set up in the "Hardware" tab. leave the "Manager GPS automatically" in "Access" tab checked
4. go to your GPS application, choose the GPS port as the outgoing port you just set up
5. make sure BT is on, restart your GPS application, and you should be able to see the incoming data from the GPS status page

enjoy!

Yup, I did the same with Fortuna Clip-On + iGuidance v2.0 combo, worked without problem.
However, I don't understand about why should we assign a Com port for "program" when the COM setting of the actual Nav S/W should be set to use the "hardware" COM port? As what you've said in Step 4, in the GPS application, choose the GPS port as the "outgoing port", but not as the "incoming port" under the Program tab.

Weird WM5.0 still, lol...