In Sunday Guitar you can choose whether you want the pedal to be a volume pedal or a wah pedal. You need to change the P-text box next to the onscreen expression pedal so that it says "Wah" instead of "Vol" followed by it's placement in the chain.
What Gear do I need?
Troubleshooting Sunday Guitar
My instrument/controller isn't connecting
My Song-Specific Patch is Different from the Demo
Customizing Your Song-Specific Patch
Sunday Keys Version 2
Using the Tonic Pad Player
Getting Started with Sunday Keys for MainStage
Troubleshooting Sunday Keys for Ableton
Getting started with Sunday Keys for Ableton