The .bmp files are labeled incorrectly. They should be labeled: uniform (for the ACUs and boots), us-helmet, ussoldier-molle (for pouches and camelbak), and vest.
This should solve the problem. Note that you can have more than one .bmp file for the same item, i.e. us-helmet 1 and us-helmet 2. That way you can have more than one .bmp file showing up in game. It is completely random though.
Steve