protected override WebRequest GetWebRequest(Uri address)
{
    var request = base.GetWebRequest(address) as HttpWebRequest;
    request.ServerCertificateValidationCallback +=
        (sender, certificate, chain, sslPolicyErrors) => { return true; };

    if (Certificate != null)
    {
        request.ClientCertificates.Add(Certificate);
        LAST_CERTIFICATE_HASH = string.Format("{0} client certificates, hash {1}",
        request.ClientCertificates.Count, Certificate.GetCertHashString());
    }
    if (SOAPAction != null)
    {
        request.Headers.Add("SOAPAction", SOAPAction);
    }
    return request;
}

2015-10-07 01:06:02.446: Certificate Hash: DCE9A718132403C7B8F1690EE7E4A6E1A99D2C74
2015-10-07 01:06:02.446: LAST_CERTIFICATE_HASH: 1 client certificates, hash DCE9A718132403C7B8F1690EE7E4A6E1A99D2C74