Besides Module (which i don’t have but seems the same) ALL korg apps are just IAA Generators and not IAA instruments.Of course they don’t show up in the instrument list.This is the most lazy IAA integration because the IAA generator is automatically supported if you update your app to the latest audiobus sdk.Basically,the Audiobus team did the work for them 
The same counts for Rebirth (or Thor).
You have to open them on an Audiotrack.And route Midi to them from a seperate Midi track (if necessary)