Issue with username validation message in asp.net identity

Question

I am using new membership system asp.net identity in my project. I want to use Email address as an Username and yes i have looked these questions already:

Configure

Answer 1

Another option would be to plug in your own UserValidator that only does the user name/email check, if it doesn't fail, it delegates to the default UserValidator, otherwise it returns an IdentityResult with the error message you want.