[Update. This is corrected with proper paths.]
I replied to a post dormant since 2017
Old Thread . Jim Fogle kindly suggested I repost here.
I've been trying to work this out for years ... adding a RealTracks style to a MIDI file and keeping the MIDI Tracks in order to create different arrangements. Finally figured it out.
Here's how at least in BIAB 2024.
1. Use the File> Open Special > MIDI file, which will give you chords and MIDI tracks.
2. Pick a RealStyle that you think would work (you can audition several and keep changing them till you're happy). You will have now nuked all your original MIDI tracks, but kept the chords. You could have kept them by moving them one by one to Utility Tracks ... but this is tedious and step 3 seems more efficient.
3. To reload the tracks go File> Import> Import Melody from MIDI FILE (the nomenclature is a little confusing as this means load all MIDI tracks to the Melody track, not the Melody track of the MIDI file.) You can also drag the MIDI file onto the BIAB GUI to accomplish this.
4. In the dialog box that opens you can load each individual MIDI track to any unused track ... Utility Tracks are the obvious choice.
5. You now have a choice. At the bottom right of the dialog box you have the option to load the tracks with the GM patch for each track. If you deselect it, the GM patches won't be included. Why might you want to do this? So you can use patches from a non-GM synth to change the voices ... and I'm not sure that with the patch not included you will get the name of the track carried over. So it may not identify.
A better choice is to load with patches included, but then if you want to use a non-GM patch you'll have to change the patch. What this means if that if you go to your synth and start auditioning patches, the synth patch you might like will not persist and change back to the patch with the same # as the GM patch in the file. If you know the bank number of your synth patch, you just immediately change to the GM patch with the same number ... taking into account that some have convention 0-127 and some 1-128.
6. Edit the patch. First, be sure you are at the beginning of the file, since that is where the initial patch message is sent. Either click on the beginning bar of the chord sheet or use notation window which shows patch number in a little colored box. Right click on the MIDI track header and select 'Edit MIDI.' I'm not going to go through the whole routine here, but you want the 'List Editor' and then 'Program' where you can search and find program change, i.e., patch. You can delete the patch number and then insert yours.
7. Bonus! You can also use this method to insert patch changes at any bar you want. Great way to change accompaniment between verse, chorus, bridge, etc.
8. More bonus! Besides changing the patch for different sections you also have access to all MIDI file parameters. Volume is a particularly useful one to insert along with patch changes for different sections.
I hope this is helpful.