Do manual from T3 version work? I can't check, if this manual actually works, because I don't have this HU.
Settings-Car settings-Extra settings-Touch area keys
In POSITION menu select place (LEFT, RIGHT, TOP, BOTTOM), where sensor buttons are located;
Continue setting like on this video.
Af far as I understand, at first click Clear in the bottom right corner, then click Set in bottom left corner. Select any free cell starting from top left, select key function, press sensor key - stored cell should change it's color. Continue, until all sensor keys set. Click Set in bottom left corner again. Check, if buttons working; if not - set them again. Use USB mouse (right mouse button = back) if something goes wrong.