Extract the Texture.rfa into a folder YOU make called "New Textures". Now (assuming you already have the plugin for photoshop) Search the File extractionforthe Texture you want to Edit. I.E "Thom_o" for the thomson. You Can use the "Magic Wand" tool or the Magnetic lasso toool to outline your weaponplaneskin (any other texture your editing) and take a picture from your personal casche and copy and "Paste into" your selection outline weapon. After your through with your changes, re-pack your texture .rfa(MAKE SURE YOU HAVE A BACK UP OF EVERY FILE(archives extures or what have you)        http://developer.nvidia.com/object/photoshop_dds_plugins.html