Well, I opened the BIAB generated midi-file on a clavinova from Yamaha (cvp 409 series). There are original Yamaha files which show exactly what I need (a real lead sheet).
The BIAB midi files showed everything, and I could customize them in every way to show bass, melodies piano parts and so on - but no chords.
Now I learn, what I need might be possible with XML-files. Is it possible to export BIAB files to an XML file and then import it to Yamaha cvp?

Thanks for the response,

Gilbert