Thanks for the info Sciamano!
yes I'm italian (but I know nothing about AZ and skyteam since before this status match I've always been loyal the other two alliances ).
Clearly the Millemiglia customer service representative didn't know much about this, as she said that trips in F on AF give 200% award miles but only 100% status miles!
Even with 200% status miles it seems much more convenient to switch to Flying Blue as they give 300% status for F trips and the gold threshold can be reached with only 40K..
I believe AZ isn't very interested in rewarding F passengers since they don't have that product in their own cabins...