HaloMods "Classic" Read-only Archive

i took the bitmap of a rock in bloodgulch (halo PC) and edited it, all i did was add a few words written on it, but when i play, they arnt there? what did i do wrong (im using adobe photoshop cs2 with the dds plugin)

lift the text out of the ground with sparkedit and save open halo see where text is the put it correctly where u want it and where the text is back on the ground with sparkedit and save
thats all i can think of