UD: I too have actually tried this on numerous occasions, but met with only limited success.

As another abeit awkward workaround, I assign the RIGHT hand to a Bass Voice, triggering the chords with LEFT hand, and playing bass lines with the RIGHT hand instead of left. A bit of a challenge at first, but once accustomed to doing it, it quickly gets easier.

The bottom line is that Yamaha needs to finally add split mode RIGHT HAND triggerable auto accompaniment recognition, freeing the LEFT HAND to play Bass Lines as in the style customarily played on an acoustic piano.

Scott