I have two sites.Each one have mailbox and cas servers.But only site a cas server is internet facing.I created a certificate for cas to use on outlook anywhere.If a user who has a mailbox on site a , try to connect outlook anywhere from external world , he cas successfully get connection.But when a user from site b try to connecto outlook anywhere from external world, he can not access. I have configured proxying on cas servers so , a user from site b cas access site a'a owa and redirect to site'b owa.But the same thing doenst work for outlook anywhere? Do i have to enable outlook anywhere for intranet cas? Or internet facing cas can succesfully redirect outllok anywhere requests to intranet cas server? I dont have a certificate installed on intranet cas server.

See my answer at: http://social.technet.microsoft.com/Forums/en/exchange2010/thread/d4eb84cf-9248-4359-9cdf-91714c3434b1