Disable Email Feature to use Google Apps


I’m attempting to configure my email with virtualmin so that I can make use of Google Apps. I have all the necessary MX records pointing to the google mail server:

mydomain.com. 3600s IN MX 1 ASPMX.L.GOOGLE.COM.
mydomain.com. 3600s IN MX 5 ALT1.ASPMX.L.GOOGLE.COM.
mydomain.com. 3600s IN MX 5 ALT2.ASPMX.L.GOOGLE.COM.
mydomain.com. 3600s IN MX 10 ASPMX2.GOOGLEMAIL.COM.
mydomain.com. 3600s IN MX 10 ASPMX3.GOOGLEMAIL.COM.

However I’m getting the following error message:

Warning - errors were found in this domain’s DNS records : This domain has email enabled, but none of the MX records ASPMX.L.GOOGLE.COM ALT1.ASPMX.L.GOOGLE.COM ALT2.ASPMX.L.GOOGLE.COM ASPMX2.GOOGLEMAIL.COM ASPMX3.GOOGLEMAIL.COM point to it. Either the MX records should be corrected, or the email feature disabled if mail is hosted externally.

I think that disabling the email feature for external hosting is exactly what I want to do. (I assume this means that the server can still send email out for password resets, etc right?) If that’s the case, how might I disable it so that I can use Google Apps instead?

Thanks in advance!