Just a suggestion - are we back to the RT in question not actually having the chord you want recorded? BIAB can take any chord entry - thanks to its midi origins - but unless the musician played what you want you'll never hear it. Can you import a midi piano from another style and see what happens?
I agree with Bob. I've tried many times and I can't get RT 742 to create AmMaj7. Because of this, I suspect that the original artist did not record this chord. Playable Realtracks, though, should be able to modify the chord to create the major 7th. This would mean manually editing each chord and freezing the track after each change. Provided there is only a single instrument, it would be straightforward. If there were multiple rhythm instruments, though, the process would take a bit more time since each instrument would need to be addressed individually.
The below video clips explains Playable Realtracks. There are a couple of sections that relate to them. The first section begins at approximately 9:00 minutes into the clip and deals with solo notes. The next section follows on from this and deals with chords. It's definitely worth watching.
Regards,
--Noel