Exchange 2007 Outlook 2011 Autodiscover

So I have Exchange Standard 2007 SP1 and Outlook 2011 on Macs. When I initially set up outlook I input exchange.domain.com as my server and of course it works internally and externally. My only problem is outlook will change it to exchange.domainmx.local when I am inside our network and I am assuming our exchange and/or autodiscover is handing out that address. I don't want to touch every machine and use the apple script to disable autodiscover. How can I change it on server side? Thank you