Delete the .IWD's and then let steam redownload them them.
I suppose you'll ask how you do that:
- Go to you Steam library
- Right click the game you want to redownload some files for
- Go to the Local files tab and press "Verify integrity of game cache"
Steam will now check if the files that is needed is there and if some of them aren't it will tell you and redownload them.
YAX. Nevermind, i think i misunderstood you question. You need to edit some CFG files in you IWD files? Exactly why?