DNS server on Plesk11

[SauliusZ]

I would like to make two name servers for mydomain.com with Plesk 11.

I have:
Domain: mydomain.com
Linux server with Plesk 11 and Business Manager on 172.168.0.1
Linux server with Plesk 11 on 172.168.0.2

How to configure ns1.mydomain.com on 172.168.0.1 so it would act as main name server?
And how to configure ns2.mydomain.com on 172.168.0.2 so it would act as slave name server?

After Plesk installation on first server, I redirected mydomain.com on it, so I can configure DNS template here and mydomain.com dns settings. But when I installed Plesk on second server, it doesn`t have domain name, so I can change only dns template settings.
I am new in Plesk and DNS settings, so I would appreciate some help.