OWA URLs for coexistance in Exchange 2007 on Windows 2008
I've inherited an Exchange 2007 upgrade from Exchange 2003 which is midway through its deployment. From my research it to me it looks if we set the default web site URL to be https://cas.domain.com/exchange, that the CAS would determine whether the mailbox exists on either the Exchange 2007 server or the Legacy 2003 server and forward the request to the proper URL (cas.domain.com/exchange or cas.domain.com/owa). However that does not seem to be the case.
Wondering what would be the best way in reality to handle the coexistance issue between Exchange 2003 mailboxes and those on Exchange 2007 in order to give folks the ability to use Outlook Web Access?