Upgrade to SSL using StreamSocket

I am working on WinRT(Windows8 Release Preview). I have a web application(in fact, a simpler XMPP Client).

I mainly use StreamSocket class to connect the Jabber Server. It gives me a good start.But I met a problem when i try to upgrade the already connected socket to use SSL.

I use StreamSocket.UpgradeToSslAsync to implement it. It throws exception like this

A method was called at an unexpected time. (Exception from HRESULT: 0x8000000E)

I have no idea why this happen. I have done all thing as the above link. I have created the socket connecting successfully. And I can receive some xml stanzas from Jabber server. Here is a picture when it runs.![enter image description here][1]

You can see the picture in a new tab.

When I click the UpToSSL button, it crashes and throw the exception as above.

Here is simpler version code:

 // xmpp is my  CXMPP  client class
 private void StartTlsBtn_Click(object sender, RoutedEventArgs e)
 {
   xmpp.SendXml("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls' />");            
 } 
 // it works fine, and i have got the reponse from server:
 //     <proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>
 // next step i should upgrade my sockey connection to ssl

    private void UpSslBtn_Click(object sender, RoutedEventArgs e)
    {
      xmpp.UpToSsl();         
    }

    async public void UpToSsl()
    {
        SendEvent.WaitOne();
        SendEvent.Reset();

        // private StreamSocket ClientSock;
        await ClientSock.UpgradeToSslAsync(SocketProtectionLevel.Ssl, ClientSock.Information.RemoteHostName);
        isSsl = true;
        SendEvent.Set();
    }  

Please give me some tips. Thank you.

I am working on an XMPP application for Metro as well, the server connection and the protocol parser are ready.

I am using three ManualResetEvents so Send, Receive and Elevate won't collide. Also be carefull as UpgradeToSslAsync dosn't accept self-signed certificates, and in that case will throw an exception.

I would really like to help you further but I try to finance myself with this, the XMPP library will be released after the application is released in the store