Starkeeper,
You can combine two voices by pressing R1 and R2 on your keyboard.. You can use the didicated blue buttons to toggle between the two and select the two sounds you wish to combine. Also you can adjust the volume level of each voice, panning, DSP return and all that other stuff.. You then just store that in a registration.. If you want the keyboard to remember just your voice settings and not the change the auto accomp everytime you press a registration button just press the accomp freeze button before you store the registration.. This is all explained pretty well in the manual. If you still need help just let me know and I'll walk you through it....

Squeak