Have an MX record for a 3rd level domain

I have mail working for continuumconcepts.com right now. My mx records point to my assigned google postini servers. Works great.

I have another server out in the wild that is completely disconnected from this network, and I have named it sfr.continuumconcepts.com. I'd like to get mail working on it as well, for test purposes (I'll be using it for other domains later).

I've added sfr.continuumconcepts.com as an mx record, but nslookup -type=mx sfr.continuumconcepts.com doesn't seem to show it yet. I don't know if I need to wait longer or if I set it up incorrectly.

Here's a screenshot of my DNS manager at godaddy. As far as I know, this is public information so hopefully I am not embarrassing myself by revealing too much. 🙂

In the MX record setup, this is the blurb godaddy gives: "MX records are for routing email that is addressed to a particular domain name. Like a CNAME record, an MX record points one domain name or subdomain to another domain name or subdomain for which an A record exists.
Entering "@" for the host name is the same as entering your domain name, minus the "www." Entering "www" for the host name is the same as entering your domain name, including the "www"."

Does this look like it's set up properly? Thanks in advance.