I have necessity to import a xml document/file but is necessary indicate a username and password (is located on a external server and is protect because contain personal data).

Is possibile with your Feed Genie extension or not?

Thanks

Feed Genie cannot pass a login credentials to a server, thus that will not be possible. Also the XML that the Feed Genie expects must have an attribute to assign it as ATOM or RSS2 feed.
So a normal XML file will not be processed.