you read the opening question ?
In this case he does not ask for anything you could not emulate with a mouse ..... because Warhammer do not allow to queue Skills in case any positional condition is not met and you want to have a fall back default skill, he would just program the mouse to first try the backstyle and miliseconds later use the "anytimer" style.
And if anyone is saying that this is not needed have no clue about the handling of visible movement and hit calculation. in fact you never know if you are truly behind your target because your client is guessing how other ppl move and just factchecking in interval. While hit and dmg calculation is normally done Serverside to prevent the easiest form of cheatin (client only manupilation). In fact on your screen is often what your gameclient is guessing and not the actual position.
So he has a valid reason to have some sort of solution for this problem - this can be NB or a gaming mouse/keyboard with macro function.
I would suggest you open another thread for general issues with NB in this case it can emulated very well with a mouse and is just used to counter a flaw in game design.