I do not own the plugin in question, but here is an example of modulating the tremolo amount with HALion Sonic SE between two fixed values using an on/off type of foot pedal. Provided your plugin supports VST automation this method should work in your plugin as well.
Arm the track hosting your Leslie plugin by activating the record or monitor button.
Right click the control you wish to control with your pedal in the Plugin Interface, choose “Learn CC”, then stomp your pedal. In this case, I can now see that when I stomp and hold my left pedal the Tremolo Rate knob jumps to 100%. When I let the pedal go it jumps back to 0%.
If your pedal only sends 0 for off, and 127 for on, you can use MIDI Insert track transformers, or a Local track transformer to convert the CC events to the desired values before they get forwarded to the plugin VST automation system.
In this example I have assigned a stomp on/off pedal plugged into my AKAI MPK261 keyboard to CC67. I want it to send a value of 34 when I stomp and hold it. I want it to send a value of 11 when I let it up. So, I’ll add a couple of “Transformers” in the MIDI Inserts tab of the track.
Note, if I wanted a toggle foot switch instead of a momentary type (one I do not have to ‘hold the pedal’), then in my case I would just program it into the MPK261 itself as a toggle rather than a held type controller. If My keyboard could not do that I personally would use some control other than an on/off type pedal…either a continuous pedal, toggle button, slider, or pot, etc.
Note, some plugins do not support learning a CC in this manner, but do have fixed CC values you can use to automate controls via MIDI events. I.E. ARIA Player does not link in with the VST automation system of a DAW, but there are plenty of hard set controls we can manipulate with CC events. Some Libraries, like the one shown below give a visual indicator as to what CC a control listens for, while some might only provide that information in the library’s documentation or help menu.
In this case I only need to figure out that tremolo can be automated for this instrument via CC22. So, I need to set up my track MIDI transformers to convert whatever my pedal is sending (CC67 in this case) to the CC22 values I desire.
Finally, some versions of CuBase might not have the option to apply transformer to a Track MIDI Insert. In that case you might still be able to build up to 4 ‘local’ MIDI transformers per track.