You should just be able to add it as an effect and S1 will automatically do the routing. It's extremely straight forward. Usually if an effect is not registered, it will output silence and you have to open the effect and register it, but you only do this once. Try reinstalling the plugin, I would install the VST3 version and see if it works. If you have both VST2 and VST3 plugins installed that are the same S1 only shows the VST3. If it doesn't show the plugin, from the plus sign on track in the console, then you probably need to check out the plugins menu. Other than that, I don't quite know, I don't use Guitar Rig6 and I don't know what's going on when you try to add the effect, it doesn't work isn't detailed enough for most trouble shooting.) Good luck.