Topic: UCX Not Working as Win10 System Microphone Input?

Is it possible to have Windows 10 use an RME input as the system microphone?  Under windows 10 options, the RME inputs are listed as options, but when I select them nothing happens.  I can see+hear the unmuted input working in TotalMix, but no volume is showing up at the "test microphone" location of windows 10 sound options.  Maybe I've done something in TotalMix to mess things up?
Sadly, certain apps require the system microphone.
Everything is working great in the professional audio apps.
Thanks


Fireface UCX via USB.
Windows 10
Reaper