如何在BasicHttpBinding中的WCF服务中进行身份验证？

[AttributeUsage(AttributeTargets.Class)]
public class CredentialsExtractorBehaviorAttribute : Attribute, IContractBehavior, IDispatchMessageInspector
{
    #region IContractBehavior implementation.

    public void ApplyDispatchBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint,
                                      DispatchRuntime dispatchRuntime)
    {
        dispatchRuntime.MessageInspectors.Add(this);
    }

    ... empty interface methods impl skipped ...

    #endregion

    #region IDispatchMessageInspector implementation.

    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        int i = request.Headers.FindHeader("username", "sec");
        if (-1 != i)
        {
            string username = request.Headers.GetHeader<string>("username", "sec");
            ... do smth ...
        }
        return null;
    }

    public void BeforeSendReply(ref Message reply, object correlationState)
    {
        return;
    }

    #endregion
}

internal class CredentialsInserter : IContractBehavior, IClientMessageInspector
{
    private string m_username;

    public CredentialsInserter(string username)
    {
        m_username = username;
    }

    #region IContractBehavior implementation.

    ... empty interface methods impl skipped ...

    public void ApplyClientBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint,
                                    ClientRuntime clientRuntime)
    {
        clientRuntime.MessageInspectors.Add(this);
    }

    #endregion

    #region IClientMessageInspector implementation.

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        MessageHeader<string> mh = new MessageHeader<string>(m_username);
        request.Headers.Add(mh.GetUntypedHeader("username", "sec"));
        return null;
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        return;
    }

    #endregion
}

[CredentialsExtractorBehavior]
public class DummyService : IDummyService
{
   ... impl ...
}

        using (DummyServiceClient c = new DummyServiceClient("TcpEndpoint"))
        {
            c.ChannelFactory.Endpoint.Contract.Behaviors.Add(
                new CredentialsInserter("_username_"));
            c.DummyMethod();
        }

  <system.serviceModel>
    <bindings>
      <wsHttpBinding>
        <binding name="wsUserName">
          <security mode="Message">
            <message clientCredentialType="UserName"/>
          </security>
        </binding>
      </wsHttpBinding>
    </bindings>
    <services>
      <service name="yourservice">
        <endpoint name="YourEndpoint"
                  address=""
                  binding="wsHttpBinding"
                  bindingConfiguration="wsUserName"
                  contract="IYourService" />
      </service>
    </services>
  </system.serviceModel>

<service>