I tried using Pakrat and PackBSP but none would work. I've made some custom sprites (for a sprite trail) and they work perfectly. But when I try to pack them they simply don't find their way into the .bsp file and are replaced by pink (pure pink, can't see any squares) textures. Other custom textures (water, logo and text with alpha channel) and models work, but sound files (.mp3) and sprites don't. I have no idea what could be causing this problem. Any help is appreciated.