Hi Tony,

I use a home built unit based on a circuit available at http://home.no/gjg/bobs/Hruby.htm
To this I have connected 2 microswitches mounted on my expression pedal and two home made knee press switches using a microswitch mounted on a Tee Hinge. With this arrangement I can operate any switch without taking my foot off the expression pedal.

Cheers
Len C.