Greetings
As Iolanda pointed out,
To accelerate the registration please prepare for us
1. a printed copy of your registration code
2. a printed copy of your passport
3. if possible 10 euro as a deposit for your key (only for people staying in Esino Lario; we will not ask it to everyone but if you have it ready makes things quicker)
My question was focused on the second point. I assume for what I have read in the responses that with my European Union ID is enought for the registration.
Best wishes.
Lluís Madurell.