Thanks again, mmlr.
Unfortunately it seems Keyboardmapping isn’t suited for situations like this…I got the Input Server restarted (the mouse moved to the center of the screen) but after that nothing popped up when pressing a key.
Another quote:
When the Input Server restarts, the mouse cursor will move to
the center of the screen and you’ll be ready to find out which
scan code is generated by each special button on your keyboard.
With this new keyboard add-on installed, an alert box pops up
every time you press an unmapped key on your keyboard.
Meanwhile