If you mute all the tracks in BB you will just get the midi chord track when saving. Dragging a RT/DR RealChart or midi track to MID will export midi chord track with midi, when enabled in Prefs.
If you want the chords as well as the chord names as midi markers just open the SGU in BB Standalone C:\bb\BBPlugin\Files\Band-in-a-Box DAW Plugin Standalone.exe
Right click on the C7 top of chord sheet for setting the drag C7 into DAW to get chord names also.