So how exactly is that setup?...Do I just click the SOA button for the domain in the DNS section and put the secondary domain name? Does anything need to be setup on the secondary, or does it get setup automagically from the primary? Again, please forgive my ignorance...this is something I have been trying to figure out for a while.
Firstly on the primary DNS - go into Control Panel > Domain Name Server Parameters
Drop down the selector box on the right hand side - select "Server Settings". When this loads - if the box next to "Zone Transfer Access" is blank you are allowing zone transfers to anyone (some people do not consider this secure!) so it would work - but if you have set a restricted list of IP's make sure you then add the IP address of your backup / secondary DNS and save settings.
On the primary DNS you then go into the SOA for the domain and enter the host name (ns1.whatever.com) of the backup MX into the secondary nameserver box. Save settings.
Then go to the secondary DNS - go into Control Panel > Domain Name Server Parameters
Drop down the selector box on the right hand side - select "Secondary Name Service for Domain" - when it loads enter the domain name and the IP address of the primary name server.
Done! Hope that helps...