I have been scouring the web for an answer to this.
I am trying to use Superior Drummer 2 in Reaper to replace my MIDI drums with real drums, however I am not getting any playback from my VST.
When I load it up in Toontrack Solo, everything plays back perfectly, but in Reaper it is silent even though I see the levels move.
The MIDI drums playback fine through Reaper, but they are not replaced. I have the AISO setup, MIDI output hardware is set on all the tracks. Everything seems to be set up the same way as any of the forums or Youtube tutorials.