Use MW modulation buss of Voyager RME whithout MIDI

[Designbureau]

Hello,
i would like to use the MW modulation buss of my Voyager RME whithout MIDI.

The manual says: "The performance control for the MOD WHEEL Buss is the Modulation Wheel itself (on the RME, it’s MIDI CC1, which is the default Mod Wheel CC message)"

I also have the VX-351 and VX-352 expanders to use the RME in a MIDI-free modular system.
How could I assign any external signal (for example the x y z touchscreenvoltages not present at the RackMountEdition) to the Mod Wheel Modulation Buss?

The manual says (EDIT mode): "2.1 PGM M-WHL SOURCE
PROGRAMMABLE MOD WHEEL SOURCE is a function that allows the user to program 1 of 8 additional modulation sources to be used when the SOURCE switch for the Mod Wheel Mod Bus is set to NOISE/PGM. Enter EDIT mode, and use the +1 button to highlight PGM M-WHL SOURCE. Press ENTER and the following Mod Sources appear:
Noise (default)
Filter ENV
Amplitude ENV
Smoothed Sample and Hold
Oscillator 1
Oscillator 2
Touch Surface X
Touch Surface Y"

no result

Help