I have configured HUB,CAS& MB role and IIS 7 for OWA on Exch2010 server with trusted certificate and published thru Forefront TMG2010
Internal OWA is working fine. But it prompts an error message "403-Forbidden: Access is denied, you do not have permission to view this directory or page using the credentials that you supplied"
Windows Server 2008ExchangeMicrosoft Forefront ISA Server