Actually, theres a techinque called UV Mapping. Im sure you know of it. A map of the UV Texture points is created, usually in a photosop format, and the image is edited there. It wouldnt be an issue to do that and just overlay the camo over the UV map, save, rinse, repeat. If I can get the model into Maya, I can create the UV map in a matter of clicks and save it as something you can open.