It's the correct bass line in the ACMP, you are missing?

If 'Yes', try to get the following web page translated:
http://heidruns-musikerseiten.de/workshops/advanced.html

It's all about using the advanced features of the Yamaha ACMP. 'A whiter shade of pale' is taken as one example for contolling the typical bass line C-B-A-G-F-...

/Ulrich