Not sure if there is a pre-defined way to accomplish the same thing but here is a code change that will allow a user to login without having to type the correct case sensitivity of the email address. The Actual Login works fine without checking case sensitivity but the AuthRequest does not.
MembershipHttpModule.cs
Line 79
Was
if (customer.Email == HttpContext.Current.User.Identity.Name && customer.Active && !customer.Deleted)
Change To
if (customer.Email.ToLower() == HttpContext.Current.User.Identity.Name.ToLower() && customer.Active && !customer.Deleted)
