I've got the textures out of the .erf files the game uses with a NWN tool for the same purpose.
But they come out to blablablah.unk etc. Which if I don't miss my guess means unknown?
what we need now is someone to make a prog to turn those textures into something we can manipulate before we squish them back into the erfs. what a pain.
I'm sure someone has the knowhow, unfortch its certainly not me.