in Qtractor, you can assign a MIDI Controller to any plugin parameter (right-click on the intended parameter slider, on the generic plugin properties dialog) or any menu command (see Help/Shortcuts...).
specific to all the Vee-One's own GUI, make sure Help/Configure.../Controllers are enabled and after that you can right-click on any knob to get to the local MIDI Controller... dialog.
you have two options:
hth.
cheers