Pier,
Perhaps you may be talking about NMEA output. The iFly does output NMEA data sentences to other devices like Autopilot, EFIS or Fuel Computers. You would just need a USB-Serial cable from our store, they retail for $25. This should then auto detect and output the digital NMEA GPS data sentences to your WIngman HUD, autopilot, EFIS or etc.
This is from the Virtual HUD site. ( Wingman accepts NMEA 018, 4800 baud.) WIthout digging into more specs, it should work.
You should be able to connect the iFly GPS via the USB to Serial Cable (Pin 3 on the DB-9 plug is the NMEA output). This should connect to the NMEA input on the Wingman HUD. I hope this helps. Please have a great evening.