You're right Gentleman, RVR is controlling but visibility is not, so even if the tower reports a very poor visibility (no RVR available), you can start the approach and decide wether to land or not.
The ATC being "african style" in that place (southern Italy) and the met report buried in a long blah blah, I then got a bit confused about the legal aspect...
This is really a case where you ask yourself "Why the hell I had this stupid doubt??"
Maybe I need a vacation, after more than one year without a single day of leave
Sorry for the waste of time.