The documentation for enabling OfficeWebApps Integration on SharePoint 2013 has some dis-ambiguity, hence not clear to us on what should the case be.
If we look at Technote : http://technet.microsoft.com/en-us/library/ff431687.aspx which is to "Configure SharePoint 2013 to use Office Web Apps"; the following is suggested.
Verify that all SharePoint 2013 web applications use claims-based authentication. Office Web Apps rendering and editing will not work on SharePoint 2013 web applications that use classic mode authentication.
Further more Technote suggests the following.
In SharePoint 2013, make sure that you are not logged in as System Account. (Whenever the currently logged on user name appears as sharepoint\system , that user can’t edit or view the documents by using Office Web Apps.)
So we are assuming that even though we used a Claim Based Authentication Model, inorder for OfficeWebApps to work, we need to configured the Trusted Identity Provider Authentication mechanism within Claims Based Authentication Model. Could we seek a confirmation is that the case OR could NTLM / FBA within Claim Based Authentication Model be used as well.
Thanks
Hubert.