I just mannaged to make it work using Octopus. Not sure exactly how I did it, but It works. I mean that Octopus starts 2 instances of WoW from the same directory and all the keystrokes are duplicated in both instances (I didn't set up any macros or key filters or bindings yet). You type something in one instance and it's duplicated in another one. Now I have to sort out what keys I want to use, set up macros, etc.