Hey, you want Witcher 2's REDkit. It comes with the "extras" on Steam in the Tools menu, and you can get it from GOG if you have the game there. Look in the Asset Browser for the w2phase and edit it from there. You might need to use the search to find the right thing, because these are hard to navigate. Use edit/find and scroll left to find "By Script Function." When you save it, it will change the copy of the file in RedKit's directories. Navigate there, copy it out, merge it into your game. I don't know what method anyone else used, but this one at least works for me. WARNING: Changing script function will clear the ability name it adds. (If, say, you're doing like I am and trying to fix some broken story abilities, this is important)