Fabfilter Pro L2 Sidechain

I cannot sidechain the Mix Group bus to a stem that is feeding it so I am wondering how to make the Fabfilter Pro L2 Sidechain work? Am coming from Pro Tools and am a Nuendo noob so any help is greatly appreciated.

https://www.fabfilter.com/help/pro-l/support/externalsidechaining

External side chaining
FabFilter Pro-L 2 offers the possibility of feeding an external signal to its side chain. This is mainly useful for stem mastering, where you want to print seperate stems with the limiting/gain reduction as applied to the full master. See Output options for more information.

Feeding a signal to a plug-in’s side-chain inputs works slightly different in various hosts. This topic describes the procedure for some of the most popular hosts around: Cubase, Logic Pro, Ableton Live and Pro Tools. To explain how it works, we use a scenario with two tracks. The first one contains the audio that we want to process with Pro-L 2, which we’ll call the main track from now. The second track contains the audio that we want to route to Pro-L 2’s external side-chain input. We’ll call this track the side chain track.


Cubase
Open Cubase and create a new empty project.
Add two audio tracks that we’ll use as main track and side chain track.
Add audio files on both the main track and the side chain track. You can simply drag audio files from a Finder/Explorer window onto a track.
Open the Mixer. In the main track, click on an empty insert slot and select the VST 3 version of FabFilter Pro-L 2 in the EQ menu (note the VST 3 icon which looks like ///).
In the plug-in header, click on the Activate Side-Chain button (right of the R/W buttons) to enable the external side chain in Cubase.
At the top of the Mixer, set the output for the side chain track to the side-chain input of FabFilter Pro-L 2.

Nuendo “thinks” side-chains differently from ProTools: You have to activate the SC-target in the plug-in first, then it will be available as routing target (AUX, bus) for the SC-source. Nuendo also doesn’t allow to create feedback-loops, which can happen in ProTools.

HTH,

I am still having trouble. Let’s say VO bus has Pro L2 and I want it the MIX bus to hit the Sidechain input of VO bus… I activate it on VO bus Pro L2 insert, but do where do I get the MIX bus sent there? The SC-target is activated on the VO bus…

edit: https://www.fabfilter.com/forum/3090/pro-l2-external-side-chaining-nuendo-8?replies=6

You´re creating a feedback loop, which is not allowed in Cubendo.