WOW, impressive! Looks like you have a lot in the pipeline.
Thanks! This is still a work in progress, though, and I haven't looked into the higher-level stuff yet (e.g. the chord tracks that many games seem to require).
Based on how that port stuff passes through to the synth I would just forward everything to the synth IKsControl.
I'm not sure about the other properties, but at least `GUID_DMUS_PROP_Volume` is not forwarded directly. Only `Id = 0` is supported and it seems to be forwarded to `Id = 1`.