SSL sockets

My problem might look stupid, but I'm a newbie in that area. I'm trying to implement a SSL server on .NET Platform with an ABL client.The problem is that I can't authenticate a SSL ABL client. What certificate should I use by default to allow my SSL server to authenticate a client.

The code of my client is as follows:

DEFINE VARIABLE h_socket AS HANDLE      NO-UNDO.
CREATE SOCKET h_socket.

h_socket:CONNECT("-H localhost -S 10010 -ssl ").

DEFINE VARIABLE mText AS LONGCHAR    NO-UNDO INIT "Test string".
DEFINE VARIABLE mData AS MEMPTR      NO-UNDO.

COPY-LOB mText TO mData NO-CONVERT.

h_socket:WRITE(mData,1,GET-SIZE(mData)).

The code of my server

static void SslListener()
{
    var server = new TcpListener(IPAddress.Any, 10010);
    server.Start();
    var client = server.AcceptTcpClient();
    byte[] data = new byte[1024];
    var stream = new SslStream(client.GetStream());

    if (AutheticateSslStream(stream) != null)
    {
        int read = stream.Read(data, 0, 1024);
        Console.WriteLine(Encoding.Default.GetString(data, 0, read));
    }
    client.Close();
    server.Stop();
}

private static X509Certificate AutheticateSslStream(SslStream stream)
{
    X509Store store = new X509Store(StoreName.Root, StoreLocation.CurrentUser);
    store.Open(OpenFlags.ReadOnly);

    foreach (X509Certificate cert in store.Certificates)
    {
        // Use all PROGRESS certificates but without any luck     
        if (cert.Issuer.StartsWith("CN=Progress"))
        {
            try
            {

                stream.AuthenticateAsServer(cert);
                return cert;
            }
            catch
            {
            }
        }
    }
    return null;
}

Thanks in advance