ASP.Internet to Wordpress SSO with HttpWebRequest

I'm trying to produce a single sign up experience between an asp.internet site along with a wordpress site utilizing a simple form Publish method. I've built an easy php page that utilizes the native wordpress functions wordpress_place_user and wordpress_signon to produce user account within the mysql db and sign them in. During my asp.internet 'create new user' page code behind, I am while using publish approach to an HttpWebRequest to transmit the needed information towards the php page.

It almost works! The brand new wordpress user is produced within the mysql database, but they're not drenched in. How do i get wordpress to log them in?

UPDATE 11/29/11. I have added the code I did previously understand this working. See below

Here's my HttpWebRequest

        Public Sub LoginToWordpress()
        'This enables single sign on between our asp.net site and wordpress.
        Try
            'get the values
            Dim uid As String = TxtLogin.Text
            Dim pwd As String = TxtPassword.Text

            'format and encode the input data
            Dim encoding As New ASCIIEncoding()
            Dim postData As String = ("&UserName=" & uid)
            postData += ("&Pwd=" & pwd)
            Dim data As Byte() = encoding.GetBytes(postData)
            Dim cc As New CookieContainer()

            'Prepare web request...
            Dim myRequest As HttpWebRequest = WebRequest.Create("http://www.mywebsite.com/speciallogin.php")
            myRequest.Method = WebRequestMethods.Http.Get
            myRequest.Method = "POST"
            myRequest.ContentType = "application/x-www-form-urlencoded"
            myRequest.ContentLength = data.Length
            myRequest.CookieContainer = cc
            Dim newStream As Stream = myRequest.GetRequestStream()

            'submit the php form for BuddyPress signup
            newStream.Write(data, 0, data.Length)
            newStream.Close()

            'Get the response
            Dim myResponse As HttpWebResponse = myRequest.GetResponse()
            Dim reader As New StreamReader(myResponse.GetResponseStream())

            'Look for cookies in the response
            If Not myResponse.Cookies.Count = 0 Then
                For Each c As Cookie In myResponse.Cookies

                    'Write the wordpress cookie to the browser
                    Dim cookiename As String = c.Name
                    Dim cCookie As New HttpCookie(cookiename)
                    cCookie.Value = c.Value
                    cCookie.Expires = c.Expires
                    cCookie.Domain = ".mywebsite.com"
                    cCookie.Path = "/"
                    Response.Cookies.Add(cCookie)
                Next
            End If
            myResponse.Close()

        Catch ex As Exception
            Response.Write(ex)
        End Try
    End Sub

This is actually the php page (speciallogin.php)

    <?PHP
    include 'wp-load.php';

    require_once( ABSPATH . WPINC . '/user.php' );
    require_once( ABSPATH . WPINC . '/pluggable.php' );

    //get the variables from the post of another page
    $u_username = $_POST['UserName'];
    $u_password = $_POST['Pwd'];

    //build the array
    $creds = array();
    $creds['user_login'] = $u_username;
    $creds['user_password'] = $u_password;
    $creds['remember'] = true;

    //log the user in
    $user = wp_signon( $creds, false );
    if ( is_wp_error($user) )
       echo $user->get_error_message();

     //see what happened
       if ( is_user_logged_in() ) {
            echo'log in failed'.'<br>';
       } else {
            echo'login success!"<br>';
       }

       wp_get_cookie_login() ;

       print_r($_COOKIE);

    ?>