Garmin software question

Has anyone tried using one of the Sparkfun GPS modules (like GS406, e.g.) with Garmin’s Mapsource and/or NRoute software? I’m assuming one could use RS-232 to interface one of these modules with a PC serial port.

NRoute is an old Garmin solution for the “I want to use my laptop as a gps” issue. Connect your GPS to the PC’s serial port, and it displays your position on the maps you have loaded in Mapsource, and offers turn-by-turn navigation on compatible maps. I just don’t know whether the software will play nice with a non-Garmin GPS unit.