Got it working on my Rift S today and it‘s very easy.
Tried it with LittleNavMap:
- start Oculus Software
- start LittleNavMap
- start MSFS and keep it in the monitor
- put on the VR and switch to MSFS
- take the right controller and press the home button
- on the upcoming bar press the + sign
- in the list select the screen you want to see in the cockpit (in my case LNM)
- press the button below your index finger and while you keep it pressed move and size the window to the place in the cockpit where you want it to stay (resize works with the controllers stick)
- release index finger
- pin it with the small sign (2nd from left) in the status line of the imported window
- go abck to MSFS by pressing the related sign in the toolbar
Works great but keep in mind that you cannot edit and work on the imported window.
My final goal is to import the mirrored Ipad with my app AirNaviagtion Pro which works together with MSFS 2020. This can by done by running Airserver on my Windows 10 and connect my Ipad via Airplay, The good thing is that as long as i can use ny Ipad „blind“ i can do this during flight too.