We have office 365 e3 with roughly 100 users. we recently added a domain to start managing accounts. We would like to setup Federation services and take advantage of single sign on and synchronize AD with office 365. right now users are using their email addresses to sign on to owa. Email/login for 365 format is [first name].[first letter of lastname]@domain.com and the internal AD usernames are formatted as [first name][first 2 letters of lastname]@domain.com .
If we start the synch and configure sso, will having the different username formats cause problems? if so, would it be best to change the username format on AD or 365(without changing the email address)
Any help is greatly appreciated.