Create a mod folder. Creare a Textures folder inside your new mod folder. Copy RaceLogos.tga from the games install location Textures folder and paste it inside your mods Textures folder. Edit the RaceLogos, best to erase a couple and put the new ones in their place or you will have to edit the playerthemes in the Widow folder.
HAve a look at one I did for the Star Trek mod.
RaceLogos.tga
http://soase.weebly.com/modding.html
http://soase.weebly.com/sins-mod-set.html