MVC IPrincipal User from WebViewPage is null - asp.net-mvc

Question

I've create a base class for my Views like this:
public abstract class BaseViewPage : WebViewPage
{
public virtual new CustomPrincipal User
{
get
{
if (base.User == null) return null;
return base.User as CustomPrincipal;
}
}
}
public abstract class BaseViewPage<TModel> : WebViewPage<TModel>
{
public virtual new CustomPrincipal User
{
get
{
if (base.User == null) return null;
return base.User as CustomPrincipal;
}
}
public override void Execute()
{
throw new NotImplementedException();
}
}
and in my model I have:
public class SecureAreaModel : BaseViewPage
{
public int MyUserID
{
get { return User.ID; }
private set { }
}
public SecureAreaModel(ControllerContext controllerContext)
{
}
public override void Execute()
{
throw new NotImplementedException();
}
}
I want to use the propertiy MyUserID but I receive this error:
Error
At this point the user is autenticated
protected void Application_PostAuthenticateRequest(Object sender, EventArgs e)
{
HttpCookie authCookie = Request.Cookies[FormsAuthentication.FormsCookieName];
if (authCookie != null)
{
FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value);
JavaScriptSerializer serializer = new JavaScriptSerializer();
CustomPrincipalSerializeModel serializeModel = serializer.Deserialize<CustomPrincipalSerializeModel>(authTicket.UserData);
CustomPrincipal customer = new CustomPrincipal(serializeModel.Email);
customer.ID = serializeModel.ID;
customer.Email = serializeModel.Email;
customer.FirstName = serializeModel.FirstName;
customer.LastName = serializeModel.LastName;
customer.Roles = serializeModel.Roles;
HttpContext.Current.User = customer;
}
else
{
HttpContext.Current.User = new CustomPrincipal(string.Empty);
}
}
Any help will be appreciated! Thx