@Html.ValidationSummary() does not work within Ajax.BeginForm

Is there any problem using @Html.ValidationSummary() inside an Ajax.BeginForm form?

I have the following scenario and I can't get validation for required fields. The form is just posted and no error is thrown either.

This is the View:

@using (Ajax.BeginForm("Register", "Account", new AjaxOptions { HttpMethod = "POST", OnSuccess = "closeDialog('RegistroUsuario')" }))
{
   @Html.ValidationSummary() 
   <fieldset>
        <legend>Cadastro novo Usuário</legend>
       <table id="changePassword">
                <tr>
                    <td class="smallField">Username:</td>
                    <td>@Html.TextBoxFor(m => m.UserName)</td>
                </tr>
                <tr>
                    <td>Password:</td>
                    <td>@Html.PasswordFor(m => m.Password)</td>
                </tr>
                <tr>
                    <td>Repetir Senha:</td>
                    <td>@Html.PasswordFor(m => m.ConfirmPassword)</td>
                </tr>
                <tr>
                    <td>Email:</td>
                    <td>@Html.TextBoxFor(m => m.Email)</td>
                </tr>
                <tr>
                    <td>Pergunta Secreta:</td>
                    <td>@Html.TextBoxFor(m => m.SecretQuestion)</td>
                </tr>
                               <tr>
                    <td>Resposta:</td>
                    <td>@Html.TextBoxFor(m => m.SecretQuestionPassword)</td>
                </tr>
                <tr>
                    <td>Ativo:</td>
                    <td><input type="checkbox" name="status" id="status" value="Ativo"></td>
                </tr>    
            </table>           
    </fieldset>
    <input type="submit" value="Criar Usuário" class="ui-button ui-widget ui-state-default ui-corner-all ui-button-text-only button-link"/>
}

That´s the Controller:

//
    // POST: /Account/Register
    [HttpPost]
    public ActionResult Register(RegisterModel model)
    {
        if (ModelState.IsValid)
        {
            MembershipProvider mp  = Membership.Provider;
            MembershipCreateStatus Status;                

            // Tenta registrar o usuário
            try
            {
                //Verifica se usuário deve estar ativo ou não no sistema
                if (String.IsNullOrEmpty(Request.Form["status"]))
                {
                    model.Active = false;
                }
                else
                {
                    model.Active = true;
                }

                //Cria o usuário
                MembershipUser newUser = mp.CreateUser(model.UserName, model.Password, model.Email, model.SecretQuestion, model.SecretQuestionPassword, model.Active, Guid.NewGuid(), out Status);

                if (newUser == null)
                {   
                    /**/
                }
                else
                {                       
                    return RedirectToAction("Index", "Home");   
                }

            }
            catch (MembershipCreateUserException e)
            {
                ModelState.AddModelError("", ErrorCodeToString(e.StatusCode));
            }
        }

        // If we got this far, something failed, redisplay form
        return View(model);
    }

And the Model:

public class RegisterModel
{
    [Required]
    [Display(Name = "Usuário")]
    public string UserName { get; set; }

    [Required]
    [Display(Name = "Email")]
    public string Email { get; set; }

    [Required]
    [StringLength(100, ErrorMessage = "A {0} deve ter no mínimo {2} caracteres.", MinimumLength = 6)]
    [DataType(DataType.Password)]
    [Display(Name = "Senha")]
    public string Password { get; set; }

    [Required]
    [DataType(DataType.Password)]
    [Display(Name = "Repetir Senha")]
    [Compare("Password", ErrorMessage = "As senhas não coincidem")]
    public string ConfirmPassword { get; set; }

    [Required]
    [Display(Name = "Pergunta Secreta")]
    public string SecretQuestion { get; set; }

    [Required]
    [StringLength(100, ErrorMessage = "A {0} deve ter no mínimo {2} caracteres.", MinimumLength = 6)]
    [DataType(DataType.Password)]
    [Display(Name = "Senha Pergunta Secreta")]
    public string SecretQuestionPassword { get; set; }

    [Required]
    [Display(Name = "Ativo")]
    public bool Active { get; set; }
}

Am I missing somenthing?

Found the problem.

The Ajax.Options target id was not set. Once I have set to the validation dom element now I get the messages.

Thanks a lot