The nicest thing after finding a workaround for a problem is always meeting someone who has an even better one.
After I posted my work around for rotating the canvas in Manga Studio with your Wacom Intuos4 tablet (a regular function of the tablet not supported by MS) Youtube user Minainerz came up with a even better solution for this.
The only thing you have to do is make sure that one function of your touch ring is prestet to Autozoom/Scroll or just Scroll or Zoom. Besides this make sure that one of the function keys is programmed with the shift-key. Yes, the same key you have on your keyboard.
The way I use it:
I have the key right under the touch ring programmed with shift. If I want to rotate the canvas instead of zooming in and out I now only have to hold this key pressed with my thumb whilst stroking the touch ring with one of my fingers.
I hope you like this solution as much as I do.
Thank you very much Minainerz!