If BBW4 writes the files wav instructions data files to the SavedTracks folder then we have to wait for the programming to be done it BBW4 as all the fixes pertain to that.
The way I see it BBW4 creates those files along with .mid in the SavedTracks folder then the PLUGIN deletes the .di files after reading them in, these can be left there and be created with a new extension from .di to .RTrackTemplate to enable them to be dropped into Reaper directly or the PLUGIN track for other DAWs.