Intento usar este código:

var makeFirefoxProfile = function (preferenceMap) {
  var deferred = q.defer();
  var firefoxProfile = new FirefoxProfile();

  for (var key in preferenceMap) {
    firefoxProfile.setPreference(key, preferenceMap[key]);
  }

  firefoxProfile.encoded(function (encodedProfile) {
    var capabilities = {
      browserName: "firefox",
      firefox_profile: encodedProfile
    };

    deferred.resolve(capabilities);
  });
  return deferred.promise;
};

  getMultiCapabilities: function () {
    return q.all([
      makeFirefoxProfile(
        {
          "browser.download.folderList": 2,
          "browser.download.dir": "D:/Automation",
          "browser.helperApps.alwaysAsk.force": false
        }
      )
    ]);
  },

Pero muestra error:Error: TypeError: profile.getTemplateDir no es una función No se como arreglarlo.