Alex, surpise yourself! Ticking Fetch AI or multiplayer in the Connect-box will show real traffic as shown on globe-adsbexchange! That 's what I was looking for, and as simple as that. On the prinscreen you see Schiphol-Amsterdam, far left is X-Plane, middle is LNM, right is globe.adsb web. The KL427 is on all 3; not AI but real.
Your application is perfect!
(PS ground vehicles are also shown with a orange plane icon, but I can live with that)