Firstoff, there is indeed a chord named, Bm(maj7).

Band in a Box recognizes it. Therefore RB should also. Since the chord could be entered and was not rejected at time of entry, there you go.

It may just be that the chosen RealTrack just doesn't have anything that will fit there.

The chords spells in close harmony, as B, D, F#, A#.

Maybe you could fool it by trying to enter D+/B


--Mac