The following is the official website for the town. There is an email address at the top of the home page. Since you have a date of birth, you could email the town and see if you can get the name of your Giovanni's parents-
Also, on the website www.familysearchlabs.org there are some records for Australia. I don't know if you will find anything there that relates to your ancestry, but this website is being updated frequently, so you may want to refer to it from time to time
If you are able to get the names of your Giovanni's parents by emailing or writing to the town, you could then rent microfilm for the town and try to get other records for his family on your own. Microfilmed records for your town are available for rental through a local Latter Day Saints family history center. Go to www.familysearch.org for a list of the local centers in your country. Records are available for the town of Marostica for the following years. To view a complete list, you must search your town in the library catalog on the website I just gave you.
Registri dello stato civile, 1806-1815, 1871-1889
Authors Marostica (Vicenza). Ufficio dello stato civile