How do i set the min and max annotation on a Property, with Data Annotations Extensions?

This is what i have tried:

```
[Required(ErrorMessage = "Dette felt er påkrævet!")]
        [Digits(ErrorMessage = "Indtast kun cifre")]
        [Min(8, ErrorMessage = "Brugernavnet skal være 8 tegn langt.")]
        [Max(8, ErrorMessage = "Brugernavnet skal være 8 tegn langt.")]
        [Display(Name = "Brugernavn")]
        public string UserName { get; set; }

```

I get the following error:

Validation type names in unobtrusive client validation rules must be unique. The following validation type was seen more than once: range