If your VST library does not provide keyswitches, you can create your own using an Instrument Rack.

1. Press the button—it will blink for 10 seconds.
2. Click on the Chain Selector of the rack.

To switch a rack’s chain, define a chain value in the Articulation Editor instead of a MIDI note, CC, or Pgm.

If no longer needed, press the Map button again to unmap. Check the online manual for details.