I think I may have found a solution to this.
When mapping buttons in Learn mode I noticed the code in the Midi In column changes when you press a button.
For example, Im mapping 'Play/Pause' to Button A on the Xone K2. I enter Learn mode and press button A. When I press down the following code displays '9E24', when I release it changes to '8E24'. And the value is then saved as the latter - '8E24'
I then manually changed the value to '9E24' and hey presto, it works.
Haven't fully tested it yet, but thought I'd share, hopefully this helps