So the Smartest House got back to me… Their comment on this:
“If the lights are driven by the dimable electronic power supply you identified , you won’t be able to use the Vision module here because of the electronics in the Vision module. The device will fail soon and it will never work correctly. Z-Wave switches need to control all loads “directly” with nothing in between so transformers, power supplies or motion sensors hard wired to the lights will always prevent regular z-wave switches from working correctly”
So I’m giving up…
I find this very curious…since you would think the power supply is just another “load” and should work just like a ballast in a fluorescent light.
So under the category of “Don’t try this at home”…
At work we have a large supply of “big” 5W barrel resistors ranging from “Next to Zilch” Ohms to “Uber” Ohms. So knowing that my multimeter probe to ground was sometimes enough of a current sink to make this work (~10M Ohm) … I brought home a 33K Ohm resistor and I used that to “short” the green switch signal to Neutral. (before anyone asks… 33K Ohm was not a guess and was not calculated it was simply the largest “surplus” 5W rated resistor that I could find)
In the circuit The voltage drop across the resistor is 2.6 volts (or a 0.0002 Watt draw) The “mystery” voltage on the “off” traveler legs of the 3 way switches dropped below 10Volts and the system started to work perfectly.
I played with it for a few minutes, did a halfhearted victory dance, and then took it all apart. The ZL7431 (Resistor free) is now driving a simple on off switch to drive the light outside of the garage.
Thanks all again… This was a great learning experience.