The registrar demands, for no apparent reason, that a.ns.yourname.it and b.ns.yourname.it be listed in NS records for ns.yourname.it if they are listed in NS records for yourname.it. (Reported May 2001.) To set this up, add
.ns.yourname.it::a.ns.yourname.it .ns.yourname.it::b.ns.yourname.itto /service/tinydns/root/data.