Yamaha DGX-670 USB Audio Not Passing to VST FX in Unify Standalone

I am using the Unify Standalone App with a Yamaha DGX-670 as my Audio/MIDI interface (using the Yamaha Steinberg ASIO driver). and the MIDI signal is working as the Inst 1 MIDI indicator flashes when I play.

Furthermore, I know the Audio signal is working as I have tested it with Tonex Standalone and I can successfully open the DGX-670 inputs plus the Input/Output Meters within Tonex show movement and activity.

However, when attempting to route the Audio in Unify, I encounter an issue:

1. I loaded Tonex inside a ComboBox on the Inst 1 layer.

2. I used Configure Audio I/O on the Tonex Node and set the inputs to the generic Input 1 and Input 2 (the only options available).

3. The meters inside the Tonex VST show no movement, and the processed audio does not pass.

Since Tonex functions properly in Standalone Mode, how do I specifically map the DGX-670's USB Audio Inputs (Portable Grand 1/2) to an FX VST within a Unify layer? Also I would like to know if there is a specific hidden plugin (like 'Audio In') or a different method required for external audio input?