Currently, Voicemod is not directly compatible with MIDI keyboards but we have found a way to make it work.
MidiKey2Key is a free software that allows you to turn any MIDI-In event into a keyboard action on your computer. All you need is a MIDI device connected to your PC that can send MIDI commands.
Here you can find more info about this software:
On the bottom of the page from the link above you will find some video tutorials on how to use it.