How can I remap keyboard keys to Wacom PTK-640 'express keys'

[James Clark]

I have a wacom PTK-640 tablet and it has a row of 8 physical buttons in addition to its pen surface.

The buttons are very rarely much use to me because it's just not very efficient to move my hand from the keyboard to the tablet. What the keys can do however, is very useful. The Tablet driver comes with features where you can assign these express keys to various functions including on-screen radial menus. I love this feature because those radial menus appear at the cursor position which is very convenient, I would use them all the time but the advantage is really lost by moving my hands to the tablet from the keyboard.

Ideally I'd like to use the Wacom driver software to assign 8 different radial menus to express keys, and use Karabiner to remap specific keyboard key combinations to those tablet express keys so I can trigger those radial menus with the keyboard. How would I go about doing this?