The solution I came up with to assigning exp toe to a foot switch was as follows.
Set a toggle CC (59) midi message out on the switch of your choice on the same channel as your helix is set to, set dim value to 0, set lit value to 127 in command centre. This goes out the midi out port thru my H9s (which have to set to midi thru) back into the helix switching the expression pedal without having to max out my volume to make the switch, Cool !!!
Of course you need to daisy chain all your midi pedals with the last one returning back into the Helix midi input, and check that midi thru is off on the Helix (Global Settings > Midi/Tempo) , to stop the midi message looping and switching between the two exp pedals 50 times a second
If you don't have or are not using external midi pedals (I haven't actually tried this but I can't see why it wouldn't work) try the above with a midi lead straight across the Midi in and out ports on the Helix.
