update:
no it doesn't work. Bummer.

I got so intent on noticing that I had a band AND MIDI to the voiceworks that I failed to notice that the MIDI instruments in the band weren't playing.

No matter how I toggle it, either the voiceworks gets the MIDI or the band, but never both.

It is SUPPOSED to allow the THRU channel to send data to the hardware port if you are using MME audio drivers with the "ROUTE MIDI THRU TO MIDI DRIVER" box checked... but that ain't happening here.

Sorry. False alarm.