When you restore a backup file made with ACC 2.0, all settings appear to populate OK to acc 2.050 beta, however the gateway manager access for users is blank. I had to re add "admin" and "internal network" to the dialog boxes in order to be able to connect into the gateway manager GUI.
Angelo, this seems weird - the information which user is allowed to access the Gateway Manager from where is stored within the Confd storage part of the backup and is not related to the ACC database.
Could you please send us the backup file in question to acc-support@astaro.com ?