How to remap orange keys on Ruckers harpsichord

If I'm using an extended number of divisions of the octave, and the "extended MIDI mapping for up to 16*128 notes" mode and the "full rebuild / extended range" option, there are three "orange" keys in the middle of the keyboard which aren't being mapped to notes, but instead seem to toggle the three registers of the Ruckers harpsichord.

I'd love to get them off the keyboard, and have those keys just play a note. It would be better to have those functions tied to MIDI controller messages (like being able to turn a pedal into a toggle switch) than notes, but just disabling them altogether and relying on the selected preset to choose which registers are active would also do.

See here for a picture of what I'm talking about:
https://i.imgur.com/gUDqjsB.png

Those "orange" notes in the middle of the range don't make a sound, but affect which strings are going to be played by other notes.

Depending on the tuning system, those keys end up being different notes, but they seem to steal notes consistently from every octave due to the extended layout business. For example, in 43edo, I end up with no F#, Gb, or Abbb. In 31edo, there's no A, Ab, or G##. In 50edo, there's no F, Gbb, or E##. Since my physical keyboard layout is a Wicki-Hayden layout based on the circle of fifths (see https://imgur.com/a/6GKIroA if curious) it's a little like using the demo version with a few random dead keys strewn about.

In 19edo, I can play all the notes, strangely enough, but, only when I play in certain octaves, it visually appears as though the orange keys are *also* being pressed... thankfully they seem to have no effect though. (This visual bug seems to happen in many situations generally though.)

As I've been typing this, I just had a possible idea for how to maybe avoid them at least some of the time -- perhaps I should map my keyboard layouts so that rather than using midi notes 0 through n-1 for n equal divisions of the octave, they instead start at 127-n or perhaps start at n and go up through 2n-1. I'm not sure yet if that would help, but I'll have to rework my keyboard configuration to try it.