Station Master Desktop does not work with some radios (notably the G90), but it does work with FlRig so you can use FLRig as a go between.

In FLRig click Config > Setup > Server

Copy the number that's in the xmlrpx port text box (or enter 12345 if empty)

Open Settings in Station Master Desktop and enter 127.0.0.1:12345 (or what ever number you have) into the com port box, select FLRig from the Radio List, and save.

Added bonus: Using this method for the IC-7300 prevents the menu lockout issue.

That's it.
Hope that helps some people.