public function _sendMail()
    {
        $date = gmdate('D, d M Y H:i:s O');

        //Send the request
        $client = new Zend_Http_Client($this->_host);
        $client->setMethod(Zend_Http_Client::POST);
        $client->setHeaders(array(
            'Date' => $date,
            'X-Amzn-Authorization' => $this->_buildAuthKey($date)
        ));
        $client->setEncType('application/x-www-form-urlencoded');

        //Build the parameters
        $params = array(
            'Action' => 'SendRawEmail',
            'Source' => $this->_mail->getFrom(),
            'RawMessage.Data' => base64_encode(sprintf("%s\n%s\n", $this->header, $this->body))
        );

        $recipients = explode(',', $this->recipients);
        while(list($index, $recipient) = each($recipients)){
            $params[sprintf('Destination.ToAddresses.member.%d', $index + 1)] = $recipient;
        }

        $client->resetParameters();
        $client->setParameterPost($params);
        $response = $client->request(Zend_Http_Client::POST);

        if($response->getStatus() != 200){
            throw new Exception($response->getBody());
        }
    }