hmm
I can tell the garmin to record tracks to the memory card. It's happy to do that and then load them from there.
Yes, it can write tracks to the card, but it can't read them from there.
Don't have mapsource - the download links seem to want me to have an earlier version installed. blast.
You can get around that by downloading and installing Garmin Basecamp or Garmin Training Center first. Then installing Mapsource will work. Though I'm not sure if it will actually run unless you also install some maps for it.
Or just use GPSBabel. Its free, and quick and simple for loading tracks.