OpnSense HAPRoxy & Remote Desktop Gateway

I’m using HAProxy v 2.0.19-aceb6cb running as a plugin on OpnSense v20.7.7.1. I have a few different sites published and working well, however I can’t quite figure out the proper method for creating a publishing configuration for Windows Remote Desktop Gateway 2019. As its a plug in for OpnSense, many of the articles/configurations aren’t as directly applicable.

My goal is to have a URL (rdg.domain.com) publishing an internal server running RDG.

Any pointers available?