[eluser]nearo[/eluser]
I realize this feature will be implemented in the next release of freakauth, but I have a super simple workaround until then.
During user updates or initial registration use the email address value as the username. You will have the email address in the database twice, but it is such a simple solution that it is worth it until the feature is implemented correctly.
I suggest changing the database structure of the username field to match the email address, which is varchar(120)