I touched on this in another thread I posted and it was suggested to me that I should save the BIAB files as wav files and then open your song in RB, and if those tracks get regenerated you still have the originals to import and then cut the newly regenerated tracks out.

I have not tried this. I have been a RB user since I got this thing like 8 years ago, but the more experienced BIAB people were who suggested that.