Dear Pete, 
I got your excellent module running on FS2002 with a Moving Terrain Vision Air which just runs great. Now I have bought FS2004 and encountered that the Magnetic Track on the Vision Air is only changing from 0° to 9°. 
I checked out the datastrings coming from FS2002 and FS2004 an found following: 
$GPRMC,xxxxxx.xx;A,xxxx.xxxx,N,xxxxx.xxxx,E,0,1,299,8,xxxxxx,1,2, 
             W*4B 
             correct should be  ,E,0.1,299.8,xxxxxx,1.2,W*4B 
$PGRMZ,410,9,f,2*0A 
             correct should be ,410.9,f,2*0A 
Is there a way to get rid of that problem ? 
Looking forward hearing from you 
Oh, regarding TCAS Out for external purposes like Vision Air or MX20 I can get you the string format-it is not NMEA. It is a special format that contains the target data. 
Regards, 
Finn