Everything worked out very good. Although we were a little bit too late, a friend of Carlo's opened the apartment and explained everything thouroughly.
The apartment ist cosy, clean and very well equipped. You have to know that the appartment is in the cellar - therefore there is no window.
The apartment is very close to the sites, it takes half an hour to walk to the central station. We really recommend the pasticcheria across the street. Great for breakfast.