Change UNDO from Ctrl+Z to /

I would like to change the mapping of UNDO from Ctrl+Z to / on the keyboard for Corel Painter Essentials 7. My wrist hurts and it will help if I have to press only one letter rather than two letters for Undoing. However, I cannot figure out how to. I am using Wacom Intuos tablet with Painter Essentials 7. Can anyone please suggest how to.