Translate Asp.Net Identity User Validations

I am using ASP.NET Identity to control the authentications in my application, the possible validations with DataAnnotation I am already doing however all the validations are in the standard in English and I would like to be able to translate them. For example, in the code below, when I try to create a user and it already exists in the database, it returns the validation "Name xxxx is already taken." How can I proceed? I can override the CreateAsync method, but I do not know the behavior of the method.

I installed the packs pt-BR:

Microsoft.AspNet.Identity.Core.pt-br 2.2.1
Microsoft.AspNet.Mvc.pt-br 5.2.3
Microsoft.Owin.pt-br 3.1.0

I put globalization in webconfig and it did not work.

I am putting the controller code, to understand a little what I mean and the method I am using. On the occasion after creating the login, you are automatically logging into the application. Following:

    private ApplicationSignInManager _signInManager;
    private ApplicationUserManager _userManager;

    .
    .
    .

    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Registrar(RegistrarViewModel model)
    {
        if (ModelState.IsValid)
        {
            var user = new ApplicationUser { UserName = model.UserName };
            var result = await _userManager.CreateAsync(user, model.Password);
            if (result.Succeeded)
            {
                await _signInManager.SignInAsync(user, isPersistent: true, rememberBrowser: false);

                return View("Login", "Account");
            }
            foreach (var error in result.Errors)
            {
                ModelState.AddModelError("", error);
            }
        }
        return View(model);
    }