however, even after SU10 API update on, it does not recognise justsim LFSB afcad. Sceneray gate numbers and GSX gate number are totally different.
When the SU10 Navdata is Enabled, GSX doesn't know anything about the actual scenery .BGL file, where it's located, etc. It simply asks Simconnect to provide the airport data it has for a given ICAO code, and that's it.
So, the first thing to check is to verify GSX at least has recognized you ARE at LFSB and not, for example, an auxiliary airport with a fake ICAO code, similar as the EBMB case for EBBR. You can check this by enabling logging in GSX and looking at the Couatl.log when you are parked there.
If the ICAO is not LFSB, just add another visibility command for that other ICAO, same as in EBBR.
If the ICAO IS LFSB, and the parking spots are wrong, it means they are already wrong at the simulator level, that is another scenery is in conflict, of the add-on scenery failed to replace the default scenery for some reason, but GSX can't do anything about that.
Note that, while when the Navdata API is Disabled, GSX was already automatically excluding ITS OWN Jetway replacement files to be searched, when the Navdata API is Enabled ( so GSX is not searching airports files anymore ), it's more important than ever to DISABLE 3rd party airports from GSX jetway replacements, otherwise the will cause a parking names/numbers/position conflict in the sim, which will then propagate back to GSX.