Ok, now my configuration is :
the server (with cpanel) with this subdomain and path:
* --> /www (but without this, the result is the same)
main --> /main.domain.it
parking domain (with cpanel)
sub1.domain.it --> /
sub2.domain.it --> /
.htaccess in /main.domain.it path is as wp write in network configuration ( with RewriteBase / )
.htaccess in /www is untouched (but if is as wp write in network configuration, it is the same)
no change in wp configuration
now :
http://www.domain.it go to http://www.domain.it
main.domain.it go to main.domain.it
sub1.main.domain.it go to http://www.domain.it
sub2.main.domain.it go to http://www.domain.it
sub1.domain.it go to http://www.domain.it
sub1.domain.it go to http://www.domain.it
Have you any idea?