If it isn't too much hassle, would you mind explaining me how you do that sort of thing, so next time I spot an unused texture I can fix it myself without begging for help here ?
I used SimPE to extract the textures for the outfits from the Sims07.package file. Since the outfits already existed (albeit with different colors) in game, I simply used bodyshop to create some new clothes based on the existing skins, and then I replaced the texture with one of the unused ones I had extracted earlier. It was actually quite easy once I had a chance to look at the files, and is definitely something you could do in the future.
The only problem I had originally was that SimPE extracts textures in a different way than BS, and I had to standardize these before it showed up properly in game.