kross 1 output dual mono audio???

[studio99]

I have a Korg Kross 1 and want to output dual mono thru the output jacks.
I have a Combi in which I have set up a split patch with the bass panned full left and the piano full right.
I want to be able to use 2 channels in the mixer so I can control the volume and EQ separately for Bass and Piano.

Cannot get it to work!

I get the piano out of the right output only.
The left mono output continues to send left and right even when the right is connected making it impossible to cleanly separate the 2.

Doesn't seem like it should work that way!

What am I missing?