DNS Cname and outside domains

[mtcook01]

I have a 110c v4.0,build0328,110718 (MR2 Patch 8) in switch mode and am having some issues configuring a Cname in the DNS. I have DNS working with our domain example.com and all Cnames such as test.example.com resolve just fine when pointed to an A Record of example.com. We have google apps manage our mail and Fortigate DNS Cnames do not appear to work with outside domains. We have configured Cnames for google apps for years using hosted DNS but I would like to use internal DNS for inside services and send the rest out. I set up a CName of mail.example.com and by googles instructions and past experience have it forwarding to Canonical name of ghs.google.com This does not resolve. I can get it work if I add a ghs.google.com A record with an IP Address, but using the domain ghs.google.com by itself does not work. Anyone have some insight, or a better way to set this up.? Thank you.