Hello AlanMead,
The Surface with Windows RT does not support Domain joining, even through Exchange. Try using a web-based client like Outlook Web App (OWA.)
KarlProp (a contributor on this board) has posted a step-by-step instruction on how to install a certificate on the Surface RT that will allow you to connect to Exchange Server. Here it is:
It is ridiculous that we have to go to this much trouble to connect - it should just work like all of the other tablets and smart phones.