| I made a midi pedal just for muting purposes but you can use anything that sends midi. The Mackie control protocol is based on midi notes and the map can be found here:
Make sure you are sending note on value of 127. That threw me for a loop for a bit.(no pun intended)
Then it Totalmix select Options, then Enable Midi Control. Then go into the setting and select the midi port(Port 1 or 2) that you want totalmix to respond to and your all set.
-Todd Matthews | 
