Unless you can map your pedal to the Spacebar (Start/Stop), the Delcom switch that I mentioned earlier will do exactly what you want. If you want to Start/Stop songs, using the keyboard is not a good solution unless you can designate a couple of keys to do that. With the current mapping, it's not a good idea. There are ways you can turn on/off the keyboard as a controller for BIAB on the fly but I think it would lead to confusion, especially during a performance. And you would have to remember what keys do what. With a designated footswitch for this purpose, much easier.

Again, I can vouch for the Delcom and happen to own one.

R