Ok, I tried to do a retexture of :falcon:'s Pinkish Costume. My texture is partially transparent, and when viewed in game, only the body part of :falcon: keeps the texture how I want it. All other part's of him have Black where the transparent parts were. If this matter's I'm using the cmpr texture option each time.
Most textures can't be transparent and trying to make it transparent will produce a black area instead. No-one has worked out how to make textures allow transparency that don't normally yet as far as I'm aware.