This is interesting. In the (English) manual on Page 31, in the section 'Controlling HX One Parameters via MIDI', in the table 'Exp Pedal & Footswitch Emulation - MIDI CC'. indicates that if you have a MIDI expression pedal, CC3 will work as an expression message as:
CC3 Value 0-127 - 'Emulates Expression Pedal (when Settings > Pedal Jack is set to “ExpFS4”)
Note that this suggests that the MIDI expression will only work if the Pedal Jack is set EXPFS4.
I have found that even with the Pedal Jack set to 'FS3/4' the MIDI expression still works.
The upshot of this is that we can use a two-button switch (on FS3 and FS4) and an expression via MIDI at the same time.
How cool is that?
