In this example we will be using Cubase SX 1, but this guide also applies to Cubase SX 2 as well as Nuendo.
1. Start out by inserting Virus|PowerCore as a VST instrument (under Devices > VST Instruments):
2. Then set up 4 MIDI-tracks that you can use with the individual parts of Virus|PowerCore:
3. When starting out with an empty Project, by default these 4 tracks will be set to MIDI channels 1 through 4. If you're not starting out with an empty Project, please verify that the MIDI-channels are set correctly on the individual tracks, by looking in the Inspector:
4. Then in order to assign the outputs of all 4 track to Virus|PowerCore, click the first track to select it. Hold down the SHIFT key and click the last track in order to select all of them. Then hold down the ALT (Windows) / COMMAND (Mac) key, and select the Virus|PowerCore in the OUT menu. Cubase has now assigned all 4 tracks to the same output:
5. Now you can use the pop-up menu in the Virus|PowerCore, to switch between the different parts in order to assign/edit the sounds:
Thank you goes out to James Booth for very kindly pointing out the ALT / COMMAND trick in Step 4.