Ciao afrricame, we say when in ROME do as the Romans do! By GIVI.
It is known as one of the best worldwide. Unless you are doing lots of rough dirt roads, then you may need something a little stronger. There are threads on this site all about luggage.
The givi outback topcase I've enjoyed a lot so far!
At the time I bought it there was no aluminium rack available from givi here in Belgium.
Maybe in Italy you can already get it.
The alternative is to buy the alu rack for a Crosstourer, which has the same bolt pattern, but you have to be confident enough to take out the angle grinder and modify it a bit to fit.
Good luck with the bike on your great road, I'm already dreaming of being back there in the summer.