[quote]I want to create a subdomain foobar.mydomain.com and have it point to a static IP address
Unless you’re on Code Monster or above, you need to have support do this for you.
[quote]Also I would like to set up a backup email server and give it a lower priority MX
Are you using us for the primary MX? If so, I would highly advise against doing this.
In general, I would advise against using a backup MX unless you really know what you’re doing, and even then only if the primary MX is going to go down a lot or is on a flakey network connection.