Renaming a user's UserName in the membership

Using Email address as UserName, I think this is the approach we are to go down.  My team writes internal applications for schools within our Local Authority to use.  They are not all integrated yet on AD's yet, each school setup differing slightly it would seem, and thus we don't want to burden them with another un-integrated userID.  So we thought about using email address as their UserName, since they all should have one, and would already know it.

My question is, can the UserName be altered at a later date without breaking the membership DB?  I assume it is the dbo.aspnet_Users.UserName field which needs updating only.  And I'm guessing there is no way to do it within the existing membership provider, I would need a custom Stored Procedure... Also, are there any hickups I should look out for when taking this approach?

Thanks,
David

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