Interesting... I did a test by putting in NS1.DREAMHOST.COM and NS2.DREAMHOST.COM and it accepted the changes. But when I tried to put my ns1.maindomain.com and ns2.maindomain.com it said they had to be registered nameservers.
I'm doing another test, may take a while to complete because of propagation.
I'm doing another test, may take a while to complete because of propagation.