@reactionz - It won't work as an initial payload as the EAS profile wants to use your enrollment userID as the exchange username. As the device isn't enrolled by that time, it can't.
As for the "fixing itself", that honestly should be seemless the first time you click mail after entering your exchange password. I haven't had any dramas with that perseonally. Is it not working for you?
@Mark - Is your issue resolved now? I noticed earlier it said you wanted to use the e-mail address as enrollment as opposed to the short name.