Estoy usando OpenId en un sitio web nuevo y estoy tratando de obtener información básica sobre el usuario, vea el código a continuación. ¿Por qué siempre es nulo lo siguiente?

var myData = response.GetExtension<ClaimsResponse>();

Y el código principal

[System.Web.Mvc.AcceptVerbs(HttpVerbs.Get)]
    public ActionResult LogOn()
    {
        var openid = new OpenIdRelyingParty();
        IAuthenticationResponse response = openid.GetResponse();

        if (response != null)
        {
            switch (response.Status)
            {
                case AuthenticationStatus.Authenticated:
                    FormsAuthentication.RedirectFromLoginPage(
                        response.ClaimedIdentifier, false);
                    var myData = response.GetExtension<ClaimsResponse>();
                    break;
                case AuthenticationStatus.Canceled:
                    ModelState.AddModelError("loginIdentifier",
                        "Login was cancelled at the provider");
                    break;
                case AuthenticationStatus.Failed:
                    ModelState.AddModelError("loginIdentifier", 
                        "Login failed using the provided OpenID identifier");
                    break;
            }
        }



        return View("Register");
    }

    [System.Web.Mvc.AcceptVerbs(HttpVerbs.Post)]
    public ActionResult LogOn(string loginIdentifier)
    {
        if (!Identifier.IsValid(loginIdentifier))
        {
            ModelState.AddModelError("loginIdentifier",
                        "The specified login identifier is invalid");
            return View();
        }
        else
        {
            var openid = new OpenIdRelyingParty();
            IAuthenticationRequest request = openid.CreateRequest(
                Identifier.Parse(loginIdentifier));

            // Require some additional data
            request.AddExtension(new ClaimsRequest
            {
                Email = DemandLevel.Request,
                FullName = DemandLevel.Request
            });

            return request.RedirectingResponse.AsActionResult();
        }
    }