You need to consult the MCU manual:-
To go into plugin mode you need to send Note 80 (G#5) - which is ‘Save’ on the original MCU mappings. And then the bank buttons swap pages. You use the remote editor to change parameter names and orders.
I’m not sure what standard commands are sent on that Behringer by default and what can be changed.
This gives you an idea of the standard MCU layout, and how Cubase implements it - and which buttons (MIDI Notes) do what:-
As the X-Touch mini doesn’t have a screen, I really recommend using an MCU emulator screen so you can navigate the MCU protocol better:-
MCU Emulator – Sender Spike (windows)
You can create a virtual MIDI port (loopMIDI application) that comes out of Cubase and into that emulator, and then from the emulator back to your X-Touch. So:-
Midi In path:
[X-Touch MIDI OUT] → [Cubase]
Midi Out path:
[Cubase] → [MCU Emulator (Screen overlay)] → [X-Touch (LED Feedback)]
I don’t own an x-touch so don’t know how easy this would be to do. Would be interested to know though, as they’re a cheap controller and if you can put together reasonable MCU compatibility with one it’s a nice option.