Even with the ability to set up separate commands to key down / key up in game, you CANNOT have a separate commands on one key down / key up, when one of those commands is IWT.

Blizzard did not give us the option to macro this specific ability. You cannot keybind IWT to a keyup command, only to a full key command. Doing so with ISBoxer is doing something you cannot do ingame on a single character.

I think having separate actions on key down / key up is a also not allowed, but looking at those API commands I'm not so sure. Having one of those actions be IWT is definitely not allowed, the way I see it.