You would only use the FTL modifiers if you have your toons specified by Shift, Ctrl, Alt etc under the Character Sets section. *for example if you had a macro on each toon for follow* Player 1 would be Shift f12, player 2 Ctrl f12 and so forth. This way when you switch to that toon the other toons know which one to follow.

Is your key your IWT that you are having problems with or actually assisting on key stroke 2? I created a complete new set of DPS keys for my IWT melee group when i played. Then i blacklisted the original set of dps keys.

I would try creating a test group called DK2 or whatever you want to. I've never had an issue with Isboxer not allowing it to auto assist.