Autohotkey or Scripts for playing with Tablet Pens allowed?

[Boooooooo]

Heyo,
at home during the holidays I'd like to use my Surface Pro with the MS Slim Pen 2 to play a little bit of mechabellum. It works performance wise, but due to the lack of custom controls and the Surface Pen not having a possibility to set the side button as a "middle mouse" input, I'd like to use something like autohotkey or something similar to change the input or create a batch file that inputs "T" or the middle mouse to change the direction of the unit.
Yes, a keyboard is possible. But for Sofa Gaming and a game that its optimised for mouse only, that would be nice to have.
Also maybe adding some scripts for camera control :)