Hi Bernie
I had a fairly complex setup going in PA3X arranger mode, using sts's.
Wouldn't want to use it on stage, too easy for something to go wrong.

I've played around with it a bit, I tend to think maybe the most foolproof way of doing it , might be in sequencer mode.
This should enable you to hopefully switch between the 2 setups.

VArranger should be set to receive midi channel 1.
Midi In korg
Midi Out Sd2

Korg will need some adjustments.

In Global
Midi Setups
Create your own user setup.
Choose "Default" Set Up,
Simply Change
Midi Channels Out
Channel 1 Track 1.(ply1 Tr 01, is mine)
Turn All the other channels to OFF
Save it as VArranger ?? to one of the slots
Preferrably the slot that sequencer normally defaults to.
( My case it's setup 3 ) if not, just make sure that "varranger" is your midi setup whenever you use the setup.
You shouldn't need to change anything else unless your Settings are different to mine.

Next I created a default Song in sequencer mode.
You don't record anything,
Goto Track Controls
Choose " External" Track 1
Save your song as Varranger

You just Load this song & midi settings when using Varranger.

Hope makes sense.