Submarine in AddOn-scenery

Hi all,
Can anyone please tell me if it's possible to make a scenery.BGL from a mdl.-file? I would like to have a submarine in my AddOn-sceneries in FSX.
Cheers,
hertzie.
Can anyone please tell me if it's possible to make a scenery.BGL from a mdl.-file? I would like to have a submarine in my AddOn-sceneries in FSX.
Cheers,
hertzie.