to know what to extract, look in the data.ini file from the plane you want your pilot to sit in
then, either, you only want this new repaint to be avbl(and somehow loose the stock pilot (not exactly correct..), and then, extract the lod and bmp and save them in the aircraft folder (the folder named aircraft, not the one you chose)
then, repaint hte bmp as desired
exemple:
using the A-6A_data.ini file
[Pilot]
SystemType=PILOT_COCKPIT
PilotModelName=PilotN1
Position=-0.35,1.15,0.85
SeatModelName=seat_f-4
SeatPosition=-0.35,1.15,0.48
MinExtentPosition=-0.85, 0.49,-0.35
MaxExtentPosition= 0.00, 1.81, 0.91
CanopyNodeName=Canopy
this can be found in "crew" section, PilotN1.LOD, PilotN1.BMP would be the files you need to extract and store in "aircraft" folder
now, if you want your skin to be considered as an extra set, some more work is required to duplicate/mod an existing pilot