How to setup a signed mobileconfig. The original post is found below.
http://www.rootmanager.com/iphone-ota-configuration/iphone-ota-setup-with-signed-mobileconfig.html
The original post is also provided as an attachment. Over-the-air iPhone Setup Using a Signed .mobileconfig File
If you are using Verisign, the intermediate CA certificates are available in the link below.
http://www.verisign.com/support/verisign-intermediate-ca/code-signing-intermediate/index.html