Billy,
The original thread was about the use of RealFlight controller with FMS, and you are talking about the use of 3rd party USB controller with RealFlight.

Any way, have you tried the following trick (from RealFlight support knowledge base):
http://www.gpsoftware.com/kb/q01-1013.htm
They say that after editing realflight.INI file, your USB controller becomes visible in RF.

Hope this helps,
Boris