What is the protocol used when such as word 2013 seeks to "connect" to an office365 sharepoint site (say) - having already been bound to a Microsoft account as a result o downloading the office suite from the office365 portal (as a registered/licensed user).
http://wp.me/p1fcz8-4Ga shows the scenario. ONe launches word, one seeks to connectup (to sharepoint online), and one adds ones custom domain name. The latter works fine in normal access to Exchange Online from a browser (talking to the local ADFS just fine), and yes apps on tablets also connect just fine to sync email. Thus interaction between MSonline and ADFS is all working fine....
Note the host is NOT on the domain (associated with the custom domain).
Note that the process works if one uses a non-custom account in the office365 subscription.
SO what happens under the hood? does the client app talk to services in the cloud, that in turn talk to ADFS using ws-trust (to validate the credentials entered in the local form)?
Is the interaction with ADFS different to how MSOnline talks to ADFS (over wstrust Feb2005) when validating a login from a POP3 client (such as an ActiveSync-based native app ...in some tablet)?