Exchange 2007 to 2013 coexistence Legacy access

Question

I’ve successfully installed Exchange 2013 CU1 (in a cloned environment so I’m no harm done
J) and most thinks seems to work but OWA and Active Sync on EX2007 mailboxes give me some headache.
I’ve created a legacy.company.com DNS record, reconfigured the virtual directories on EX2007 and set OWA to FBA/basic.
OWA IS redirected to EX2007 legacy URL but authentication is not being passed through and you have to enter username password again at the EX2007 OWA site. Active Sync (tested on Iphone) works but you have to enter password at every sync.
What could I be missing?
/Søren Emig

Answer 1

Fiona,
Reading through the first technet link, it makes it seem as though redirection should happen silently and the FBA should be passed to the CAS2007 server seemlessly.  
CAS2007 will consume that hidden form's data, authenticate the user and:
Retrieve and render the user's mailbox data from the Exchange 2007 mailbox server and provide the data view back to the user.  The response will contain an FBA cookie for the legacy namespace, and from that point on all user activity within the session
will go to legacy CAS only.
Or proxy the request to the Exchange 2003 mailbox server and provide the data view back to the user.  The response will contain an FBA cookie for the legacy namespace, and from that point on all user activity within the session will go to legacy CAS
only.
That sounds like the OWA page should render without the user logging in a second time.  Also, if you look at the docs for Exchange 2010, the scenario is the same. http://technet.microsoft.com/en-us/library/bb310763(v=exchg.141).aspx
CAS-01 will look for an Exchange 2007 ExternalURL property
that has an ExternalAuthenticationMethods setting
that's identical to theInternalAuthenticationMethods setting
on the Exchange 2010 Client Access server. If the settings match, CAS-01 will redirect to this external URL. If source and target CAS have Forms Based Authentication (FBA) enabled, the source CAS issues a hidden form back to the browser that contains the user’s
credentials and FBA settings, along with the redirect URL. This is transparent to the user.
Now if the SSO code for Exchange 2013 is not ready, that is another matter.  But there is no documentation that I could find explicitly stating this.