According to this tid (
bin/search/searchtid.cgi?/10014559.htm) the MX record is to be created in
association with the "big AT." This does appear to be the only way to get
a valid response when doing an nslookup (set type=mx), yet the response
indicates the mail server is the DNS server, which is not the case for
us. How do we create an MX record that will be associated with our actual
mail server?

Thank you in advance for your kind assistance.