Thank you. You guess correct.
I'll test that intent tomorrow, I'm sure it works.
I see better that Cerberus app, does not call the intent, but just show a msgbox and ask the user if he wants to hide the notification, then automatically apply this settings.
During installation I see Cerberus asks the permission to modify system settings.
So the new question is, how to automatically set the app to hide the notification (and which permission is required).
I did some tests yesterday and looks like the service runs forever also when notifications are disabled (otherwise Cerberus would not works ....).