I'm not too sure if this would help, but in Tyros it is possible to record a midi chord sequence in the multipads (with looping enabled if wanted, in just one button or different sequences in up to all 4 buttons), and have the chord sequence "drive" a Style through midi as if the pads were playing the left hand. If required you can also set the keyboard up so you can play over its length- say a piano piece - at the same time without worrying about whether the correct backing chords are being triggered manually because the pads are in control. It's a bit like using a midi backing song, but more easily turned off and on and looped, and with a choice of up to four easily accessible.
It works with Vocal Harmony also.

It involves setting up a simple Midi template for Tyros and linking midi out (from the pads) to midi in (chord detect) via cable.
I can post more detail if required. Sorry I don't know if it can be made to work in other arrangers including PSR3000, but I'm sure others will be able to comment.

John