Greetings,
what was the question
On the Airbus there is a page called PREDICTIVE GPS, it will show RAIM availabilty at a specific waypoint (destination for example) at a specific time (ETA)
On B777 the GPS receiver will compute a data relevant to RAIM availability and sends it to AIMS.
So I guess that if you are on Boeing world on top of the NOTAMS specific to GPS you need to have RAIM holes.
Because you cannot shoot an approach using GPS as main sensors if RAIM is not available.
RAIM needs 5 sats (if you are baro aided) 7.5 deg above the horizon.
Now North of Italy is mountaineous? may be mountain shaddowing is reducing the number of sat you can receive.