Hi gebux, I would like to point out that in Italy the street number identifies the access point (entrance) and NOT the entire building. In fact, a building can have multiple entrances and consequently multiple street numbers. 
So you have 2 options: 
1. If you know exactly the position (entrance) of the street number you are mapping, put all the address tags on a node on the perimeter of the building (also adding the entrance tag on the same node); 
2. If you do not have this precise information, you must put all the address tags on an adjacent node but DETACHED from the polygon of the building. 
I have already made the necessary corrections. 
Thanks and Happy Mapping!