I also sold a canopy to Paval last year (a new Spectre). I sent it registered post to Russia from the U.K and Paval paid me up front through paypal. The canopy arrived fine and wasn't opened by customs. I see that he took the same precautions with this guy in Italy, asking for a contract to be signed and getting ID, etc.
It's always risky buying stuff on-line from unvetted private sellers and when you drop a wedge of cash on something like this, you just hope the guy comes through.
I also think that the seller has some obligation (unless he is a cu*t, in which case he wouldn't care!) to see that the buyer receives the goods intact and lodges any insurance claims from the senders end.
I don't like the chances of a Russian guy living in Moscow trying to get money from the Italian postal service's insurance company.
Sorry you have been bitten by this one Pavel. Hopefully this guy Ferdinando is decent enough to help you out and it's just a miscommunication.....
Matt