If you want the same notes try Native Instruments Bandstand and set you midi out to use it. I think there is a folder in BIAB called

Before: Oh_Darling_V1_Beatles.kar.mid
After: Oh_Darlin_mid ... Sample.mp3

To implement better functionality in Band-in-a-Box with the Native Instruments Bandstand soft synthesizer plugin--

1: Exit Band-in-a-Box if it is running.

2: Please make sure that you have installed the Band-in-a-Box 2006 build 220 update (or later).

3: Move the included BB/Bandstand Technical Notes/AsstSettings.ini file to your Band-in-a-Box bb folder.

4: Please read the UsingBandstandWithBIAB.pdf file to understand what, if anything,
you may want to adjust in the new AsstSettings.ini file.