I am currently trying to implement this feature but the link to: http://ugx-mods.com/downloads/tutorials/trem_hintstrings.iwd doesn't work anym...
Well so far we don't even have a damn FX editor to even make FX with, so until that happens really nothing to do with custom fx is really that possible. You have to do it all by hand and its dumb.
Did you spawn them in or got them from the box? If it's like WaW, spawned in ones from commands don't work.
Sorry, not quite sure how to invert separate channels with gimp. Nevermind, edited OP