ASMX：将用户凭证从客户端发送到服务端的问题

Question

我咨询这两个网站只是为了知道如何使用soap header

https://www.codeproject.com/articles/4398/authentication-for-web-services-using-soap-headers

https://www.codeproject.com/Articles/27365/Authenticate-NET-Web-Service-with-Custom-SOAP-Head

我也以这种方式开发我的网络服务。看到代码

namespace CustomAuthWithHTTPModule
{
    /// <summary>
    /// Summary description for SecureWebService
    /// </summary>
    public class Authentication : SoapHeader
    {
        public string User;
        public string Password;
    }

    public class SecureWebService : WebService
    {
        public Authentication authentication;

        [WebMethod]
        [SoapHeader("authentication", Required = true)]
        public string ValidUser()
        {
            if (User.IsInRole("Customer"))
                return "User is in role customer";

            if (User.Identity.IsAuthenticated)
                return "User is a valid user";
            return "not authenticated";
        }

    }

}

在我的控制台应用程序中，我只需添加Web引用即可创建上述Web服务的代理。问题是AuthHeaderValue或UserCredentialsValue这两个属性都没有在客户端公开，我可以通过它发送用户凭据。看我的客户代码

ServiceReference1.SecureWebServiceSoapClient xx = new ServiceReference1.SecureWebServiceSoapClient();

            ServiceReference1.Authentication a = new ServiceReference1.Authentication();
            a.User = "Hello";
            a.Password = "Hello";
            xx.AuthHeaderValue  or xx.UserCredentialsValue // not being expose

指导我犯错的地方。我正在使用VS2013 IDE。感谢