public static void TestSignFile(string fileName, X509Certificate2 signCert)
        {
            StreamReader reader = new StreamReader(fileName);
            string text = reader.ReadToEnd();

            var oSigner = new CAdESCOM.CPSignerClass();
            CAPICOM.Certificate cert = GetSignerCertificate(signCert.SerialNumber);
            if (cert == null)
                return;
            oSigner.Certificate = cert;
            oSigner.TSAAddress = "http://www.cryptopro.ru/tsp/tsp.srf";
            
            var oSignedData = new CAdESCOM.CadesSignedData();
            oSignedData.Content = text;
            var sSignedData = oSignedData.Sign(oSigner, true, CAPICOM.CAPICOM_ENCODING_TYPE.CAPICOM_ENCODE_BASE64);
            var date = oSigner.SignatureTimeStampTime;
        }
        private static CAPICOM.Certificate GetSignerCertificate(string serialNumber)
        {
            Store oStore = new StoreClass();
            oStore.Open(
              CAPICOM_STORE_LOCATION.CAPICOM_CURRENT_USER_STORE,
              "My", CAPICOM_STORE_OPEN_MODE.CAPICOM_STORE_OPEN_EXISTING_ONLY |
              CAPICOM_STORE_OPEN_MODE.CAPICOM_STORE_OPEN_READ_ONLY
            );
            Certificates oCerts = (Certificates)oStore.Certificates;
            Certificate cert;
            for (int i = 0; i < oCerts.Count; i++)
            {
                cert = (Certificate)oCerts[i + 1];
                if (cert.SerialNumber == serialNumber)
                {
                    return cert;
                }
            }
            return null;
        }

oSigner.UnauthenticatedAttributes.Add(oStamp.Export());

TSPCOM.TSPStamp oStamp;