protected function _getBinaryNotification($sDeviceToken, $sPayload, $nMessageID = 0, $nExpire = 604800)
	{
		$nTokenLength = strlen($sDeviceToken);
		$nPayloadLength = strlen($sPayload);

		$sRet  = pack('CNNnH*', self::COMMAND_PUSH, $nMessageID, $nExpire > 0 ? time() + $nExpire : 0, self::DEVICE_BINARY_SIZE, $sDeviceToken);
		$sRet .= pack('n', $nPayloadLength);
		$sRet .= $sPayload;

		return $sRet;
	}