Not really sure if this is what you mean, but to create a custom texture for walls you need to make the 512x512 or 1024x1024 texture in a paint program (I use GIMP, it's free), save it as a .tga / .dds image and throw it into the texture bank. Then copy the files of the segment you want the texture to be applied to, rename them to a name of your choice (so you don't override an existing segment you already have in the library), then in the FPI file of your new segment, change the texture so that it finds the texture you made and placed in the texture bank. I'm not sure how to apply shader affects to weapons...yet.
Success is not final--failure is not eternal.
