How to setup custom nameservers with 1and1 control panel?

First create respective subdomains like ns1.mydomain.com and ns2.mydomain.com:

• Go to 'Administration' > 'manage domains'
• Click the little arrow on 'New' (left side of manage domains toolbar) and click on subdomains
• Type ns1 for the subdomain and choose your domain from the drop down on the right
• Go back to manage domains and click on 'DNS'
• Enter ns1.mydomain.com for the primary nameserver and ns2.mydomain.com for the secondary nameserver