how do you get your registrar to recognize your new nameserver?

[Bennett Hui]

I've read through chapter 4 of Oreilly's DNS and BIND book as well as
several DNS HowTo documents online.  I think I've got named setup the way I
want it with all the appropriate config files, and it appears to be working
fine.

A while back I registered a domain name through register.com (call it
mydomain.com).  The nice thing about register.com is that they provide a web
interface where you can manage all your DNS/mail/IP alias configuration
needs.  Through this web interface, i created a subdomain called
ns1.mydomain.com and ns2.mydomain.com.  Each one resolving to the IP
addresses where I have setup my primary and secondary nameservers,
respectively.

Recently, I've registered a new domain name through OpenSRS (opensrs.org) --
call this new domain: mynewdomain.com.  I've tested that this domain
resolves to the right place after setting up my new primary DNS server
(tested using nslookup).  nslookup displays the right information that I
entered into the named reference files, so the nameserver appears to be
working fine on the local machine where named resides.   However, when I go
to opensrs to change my nameserver for mynewdomain.com to my newly setup
nameserver, it comes up with the message:

Unable to add nameserver: Command failed: unable to verify existence of
nameserver ns1.mydomain.com

I know that the address ns1.mydomain.com is resolving to the IP address of
my new nameserver because it's using register.com's working DNS server.
Plus, I've been able to successfully ping this domain name from any remote
machine.  Yet, my registrar says that it cannot verify the existence of this
nameserver.  My question is this: is there something extra I need to do for
opensrs (or any other registrar for that matter) to recognize that this new
nameserver actually exists?  Am I supposed to notify someone or something (a
root server, perhaps) that I have created a new nameserver?

Any help on this matter would be much appreciated.  Thanks.