Tried the 3d modelling board
(sorry, I dunno modelling for crap - apart from the "models" I sleep with)
;D
Normally, all ya need to do is to convert JPEG's or TGA's to PAA/PAC images,
and then use a tex.swapper tool to add them to the p3d file.
But that's re-textured orig. models... dunno about home made p3d's
as I said, try the p3d modelling board