The process described behind doesn't Works.
1) Buy the GSX level 2 and receive you serial after order validation
2) Start P3D or FSX
3) Switch to windows mode NOT FULL SCREEN (ALT+ENTER)
4) Go to ADD on / Addon manager menu
5 From the left to right list, choose:
- FSDreamTeam
- Gxs Level 2 Expansion
6) Follow the guidline proposed
7) After the activation message, switch back to full screen (ALT+ENTER)
Tips go back to the same menu and choose on left side "Backup RegKey" and store the result in same folder of you installer backup for future use
Hope it help
Works perfectly
NB: Outside sim updater will works after