I want to use Exchange Federation to exchange free/busy-information with a remote company. I have set up the federation by following the documentation and the trust with the MS Gateway is successfully established. The documentation says that I have to register a CNAME for autodiscover in DNS and let this point to an Internet-facint CAS-server. I do not have an Internet-facing CAS, I am publishing OWA through Forefront TMG and the CNAME is pointing to the TMG-server. Do I have to do any changes in Forefront? Publish any new URLs?