I don't use DP, so it is a little hard for me to describe what to do. Best way is to look up in the manual / youtube and see how to setup a controller.
In Cubase I would setup my controller to change the automation data of a MIDI track that is linked to VEP, or to the VEP isntance parameter. When linked to automation of a MIDI track (for example Midi CC), just go to VEP, klick on the "L" button in the automation "MIDI Controllers" window and press / move your controller-knob/button/fader. Set the destination on the right side (which parameter should be controlled).
For parameter mapping I would select my VEP instance and map the controller to the VEP parameter automation.
Sorry, but maybe someone here has the knowledge how to do this in DP....
Best, Ben