Can you change the URL autodiscover returns?

Hi,

I have a newly configured Exchange 2013 server. I'm running the "Test E-mail AutoConfiguration" from Outlook 2013.  The test returns a security alert because my certificate is not valid for the returned server FQDN. It returns exchange.ad.mydomain.com. How can I configure my server to return exchange.mydomain.com instead?

Best Regards,
Stian H. Nesbø