I have used PG Music's program, 'Power Tracks' www.pgmusic.com
I set Power Tracks to record, then play the keyboard pattern (like just a 'C' chord....using the intro/ variation/ ending). Save the recording as a midi file. The big question then is there a conversion program for midi to Yamaha 'style'? I would suggest asking that question on a Yamaha forum...they should be able to direct you...if there is that type program. In the Casio world...Casio has a converter program (for the wk series) on the company download site. That wouldn't help you for the Yamaha conversion, though. I hope you can find the help you need.