I wrote before about my great grandfather's birth certificate, just for information before responding I already have been through the following sites:
ancestry.com
ellisisland.org
1920 and 1930 census ( he did not live in New Jersey when hen migrated)

I did however find my grandfathers:
WWI ...

Wondering if I can get some help not having much luck!

I know that my great grandfather was born in Naples, but i do not have his birth date, just the year he may have been born. I do know he then moved to Ustica, and married my great grandmother.

any suggestions since I do not have the actual ...

I am going crazy! I need to try and apply for dual-citizenship and I cannot find my grandfather's natualization or citizenship records.

In addition, I would like to know how I may obtain his birth certificate from Palermo Italy? Trying to get a phone number from the internet but I cannot find one ...