//МЕТОДЫ ASYNC_CODE
function extract(from, what) {
  var certName = "";

  var begin = from.indexOf(what);

  if (begin >= 0) {
    var end = from.indexOf(", ", begin);
    while (end > 0) {
      if (this.checkQuotes(from.substr(begin, end - begin))) break;
      end = from.indexOf(", ", end + 1);
    }
    certName = end < 0 ? from.substr(begin) : from.substr(begin, end - begin);
  }

  return certName;
}

function checkQuotes(str) {
  var result = 0,
    i = 0;
  for (i; i < str.length; i++) if (str[i] === '"') result++;
  return !(result % 2);
}

//МОЙ КОД
function showCertificateDetails(oCertificate, isFromContainer) {
...
      this.currentSubjectNameFIO = this.extract(
        yield oCertificate.SubjectName,
        "CN="
      ); // Сохраняем текущий subjectName в глобальной переменной
...
}

function SignCreate(currentSubjectNameFIO, dataToSign) {
  return new Promise(function (resolve, reject) {
    cadesplugin.async_spawn(
      function* (args) {
        var oStore = yield cadesplugin.CreateObjectAsync("CAdESCOM.Store");
        yield oStore.Open(
          cadesplugin.CAPICOM_CURRENT_USER_STORE,
          cadesplugin.CAPICOM_MY_STORE,
          cadesplugin.CAPICOM_STORE_OPEN_MAXIMUM_ALLOWED
        );

        var oStoreCerts = yield oStore.Certificates;
        var oCertificates = yield oStoreCerts.Find(
          cadesplugin.CAPICOM_CERTIFICATE_FIND_SUBJECT_NAME,
          currentSubjectNameFIO
        );

        var certsCount = yield oCertificates.Count;
        if (certsCount === 0) {
          err = "Certificate not found: " + currentSubjectNameFIO;
          alert(err);
          args[1](err);
        }
        var oCertificate = yield oCertificates.Item(1);
        var oSigner = yield cadesplugin.CreateObjectAsync("CAdESCOM.CPSigner");
        yield oSigner.propset_Certificate(oCertificate);
        yield oSigner.propset_CheckCertificate(true);
        yield oSigner.propset_TSAAddress("http://cryptopro.ru/tsp/");

        var oSignedData = yield cadesplugin.CreateObjectAsync(
          "CAdESCOM.CadesSignedData"
        );
        yield oSignedData.propset_Content(dataToSign);
        try {
          var sSignedMessage = yield oSignedData.SignCades(
            oSigner,
            cadesplugin.CADESCOM_CADES_X_LONG_TYPE_1
          );
        } catch (e) {
          err = cadesplugin.getLastError(e);
          alert("Failed to create signature. Error: " + err);
          args[1](err);
        }
        yield oStore.Close();
        return args[0](sSignedMessage);
      },

      resolve,
      reject
    );
  });