If you are using a GPS that isn't directly supported by Cartographica's File > Acquire GPS Data command, there are still options to working with the GPS Data.
Of course, we'd like to know what kind of GPS you are using, so make sure you leave us a feature request in the forums. If we get sufficient requests for that device (or family of devices in the case where supporting one is similar to supporting all), then we'll consider putting it in a future release of LoadMyTracks and Cartographica.
In the meanwhile, check with the manufacturer or support groups for your device and see if there is another package that can download data from the GPS and convert it into GPX-format files. If there is, then you're set, because Cartographica will load those files using the File > Import Vector Data… command.