I had that problem asswel when i put the
75 in the game. First i tried to put it into the .big file but that's so crappy and it takes a hell lot of time.
What you have to do is:
in your generals decory make file called art, in that you create two files called textures and w3d. Put you skins in the texture file
then attach the skins with renx then export the model to the w3d map and YEA it works fine ingame
ok it may seem if i'm a pro now but actually i learned it at the best tutorial i've seen about this (deezire you should put this one on you site):
http://www.killasmods.tk/