Hi Annep,
PilotAware is configured so that it's first choice is its own GPS, because we had some issues when running it off the GPS in FlarmMouse (mainly due to the small size of the FlarmMouse GPS antenna), but if you simply remove the PilotAware GPS, it should automatically run on the GPS data from your PFC, provided the PFC is configured to output both FLARM Data and Navigation Data.
That will then allow you to configure the 'unused' USB port for ADSB out.
Regards
Peter
(PilotAware Engineering Team)