function serialize($charset_encoding='')
		{
			if ($charset_encoding != '')
				$this->content_type = 'application/json; charset=' . $charset_encoding;
			else
				$this->content_type = 'application/json';
			$this->payload = serialize_jsonrpcresp($this, $this->id, $charset_encoding);
			return $this->payload;
		}