How to translate IdentityResult error messages to Swedish when using Identity.EntityFramework

Question

I need to translate the error messages of IdentityResult using Microsoft.AspNet.Identity.EntityFramework to swedish. There are no available libraries to help solve this. Do I need to override Identity classes instead? Any good solution?

Here is an example code:

   public async Task<ActionResult> RegisterUser(RegisterUserViewModel model)
    {
        if (ModelState.IsValid)
        {
            var user = new ApplicationUser { UserName = model.UserId, Email = model.Email };

            var result = await UserManager.CreateAsync(user);
            if (result.Succeeded)
            {
                //save the user
            }
            else 
            {
                //errors can contain messages like The user email is already or The username is already taken
                foreach (var error in result.Errors)
                {
                    ModelState.AddModelError("", error); //translate the error
                }
            }

        }
        return View(model);
    }