Does not look like it. In the manual it says the USB port is designed to be used with editing software on a computer and the pedal can be used as sort of audio interface.
Why don't you really learn to use the Digitech processor to its full advantage. They are pretty good processors and can do all the WAH effects and many other things and probably better than the Sonitus effects anyway. Use the pedal for what it is intended.
What you want to do could probably be achieved by connecteing an expression pedal to something like an M Audio keyboard controller and then using ACT to assign the midi/USB signals to control whatever you assign it to.
If you don't want to get a keyboard controller with a pedal input there are things like this that allow you to connect a pedal directly to the midi data stream in your system:
http://www.midisolutions.com/prodped.htm