yeah ... what HE said!
Been doing that for most of my career. Love playing my own bass lines. In previous Yamaha models, you had to use the lower sound and reassign the arranger to follow the right hand .... too many hoops. I love the layout that Korg uses for this - there is a simple button that shuts off the accompaniment bass and sends it to the left zone of the keys.
My set up is refined one (well, 3) steps further by assigning the programmable buttons to toggle on/off, the lower bass tone (which I prefer for manual bass), the 1-5 arranger tracks and the auto bass track. It makes for seamless transitions from auto to manual within a song or medley.