To set your Private NameServer settings go to:
Domains > My Domains
Then select the 'Manage Domain' or click the selection of the domain name you want to change the settings for.
Then click on the 'Private NameServers' option from the manage tab in the left
Enter the 'NameServer' you want to register GLUE record and enter the 'Ip Address'.
Click Save changes. and That's it.!!