Hello Olaf,
The Hauptwerk VST plug-in is a multi-channel VST instrument, with 16 pairs of stereo audio channels.(32 channels in total). (With the Hauptwerk VST Link selected as the audio device in Hauptwerk, if you scroll down the '
General settings | Audio device and channels ...' screen you will see that the first 32 entries are listed as stereo pairs, and the channel numbers above 32 are listed with '
channel not available on this device'):
I don't have Cubase installed at the moment, and I don't remember off-hand exactly how you configure Cubase tracks to use the various channels that a multi-channel VST instrument provides, but I know it's easy to do, and Cubase's documentation will cover that.
With some VST hosts, when adding a multi-channel VST plug-in to a project the host will ask whether you want to add it as a stereo-only plug-in, or as a multi-channel plug-in (16 stereo pairs, in the case of the Hauptwerk VST Link). If Cubase asks that (when adding the plug-in to Cubase's instrument rack) you would need to select the latter. It might also/instead ask you whether you want to create audio tracks for each of the 16 stereo audio channels that the plug-in provides. If it doesn't then you could probably create the audio tracks individually yourself, selecting the VST instrument's appropriate audio channel pair for each track (channels 1+2 for the first track, 3+4 for the next, etc.) as the audio track's audio source.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.