I read the following instructions from the wave arts site…
1. Open “VST Connections” in the Devices menu.
2. Click the Group/FX tab.
3. Click Add Group and select the “Quadro” option from the configuration menu (in the More… section).
4. Control-click on the new group and select “Add Child Bus to (group name)” and select Stereo.
5. Repeat step 4 and select Stereo (Ls Rs). You should now see the two child busses under the new quaddro group.
6. Create a TrackPlug 5 ExtSC instance on the Quadro group track.
7. For the audio track that you want processed with TrackPlug, set the Output Routing of the track to the “Stereo” output of the group you created.
8. For the track you want to use as sidechain to TrackPlug, set the Output Routing of the track to the “Stereo (Ls Rs)” output of the group you created. Alternately, if you still want to hear the material on this track on your mix, you could set up a Send which is routed to “Stereo (Ls Rs)” of the group.
9. Enable one of the dynamics modules in TrackPlug (Gate, Comp1, or Comp2), and select one of the “Ex …” sidechain options. You can click on the “Mon” button to hear and verify that the sidechain is set up properly.
I tried this and got stuck on number two since there was no group/fx tab on the devices menu. Futhermore, I’m under the impression that cubase uses only vst, and does not support either AU or Rtas, which are the listed formats in which external sidechaining works anyways. Are these directions some sort of workaround for making the VST acheive sidechaining? Can this be done on Cubase LE? This method does not seem to be possible.