从 Google 服务帐户编辑 Google 日历事件:403

I want to create new event at google calendar from Service Account. I can access correctly and print a list all my calendars. But when I want to create a new event the response is 403 Forbidden.

我的代码:

require_once 'src/Google_Client.php';
require_once 'src/contrib/Google_CalendarService.php';

session_start();

const CLIENT_ID = 'XXXXXXXXXX.apps.googleusercontent.com';
const SERVICE_ACCOUNT_NAME = 'XXXXXXXXXXXX@developer.gserviceaccount.com';

const KEY_FILE = 'google_src/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX-privatekey.p12';

$client = new Google_Client();
$client->setApplicationName("APP_NAME");

if (isset($_SESSION['token'])) {
 $client->setAccessToken($_SESSION['token']);
}

$key = file_get_contents(KEY_FILE);
$client->setClientId(CLIENT_ID);
$client->setAssertionCredentials(new Google_AssertionCredentials(
  SERVICE_ACCOUNT_NAME,
  'https://www.google.com/calendar/feeds/MY_CALENDAR_ID/private/full/',
  $key)
);

$client->setClientId(CLIENT_ID);
$cal = new Google_CalendarService($client);
$event = new Google_Event();
$event->setSummary('Bon dia pel matí!');
$event->setLocation('Somewhere');
$start = new Google_EventDateTime();
$start->setDateTime('2012-08-06T10:00:00.000-07:00');
$event->setStart($start);
$end = new Google_EventDateTime();
$end->setDateTime('2012-09-06T10:25:00.000-07:00');
$event->setEnd($end);

$createdEvent = $cal->events->insert(CALENDAR_NAME, $event);

和服务器响应:

(403) Forbidden

有什么想法吗?也许其他范围，或允许编辑事件(我不知道我可以在哪里配置它，我已经搜索过了，承诺)