Overview of Exchange Server 2007 CAS Proxying and Redirection

Thanks for this article.  One thing I'd like to request is how Autodiscover works in this situation as well.  Based on what I have read, I believe it works in the following way. You should have autodiscover.domain.com point to your Internet facing CAS.  So let's say you have two sites, one in Europe and one in US.  If a user who is external in Europe contacts the internet facing CAS in USA and hits the autodiscover, it should be presented with the External URLs.  The Autodiscover should present the external URLs for the Internet facing CAS server who will then do Proxying or Re-Direction depending on if your Europe CAS has externalURL configured.  Am I correct in my assumption?