1. Bluetooth,
2. SPP-S (Serial Port Profile), and
3. The watch needs to send full NMEA 0183 (GPS) data via its SPP-S profile.
I'm not sure your watch has this, as it's most likely supposed to be used to record its own location rather than exporting raw GPS data via Bluetooth (i.e. it's supposed to be used as a GPS running watch, not as an external GPS receiver).
My last BB was a 8120 and I used a GPS puck (about the size of a box of matches) paired with my BB to do GPS. Worked like a charm. Now I have a 8900 and the GPS is built in. SO convenient! ;-)