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    public void sendOut(MessageExchange exchange, NormalizedMessage outMsg, HttpServletRequest request,
            HttpServletResponse response) throws Exception
        {
        // define a DataHandler (see Java Activation Framework)
        DataHandler dh = null;

        // if the out message received has no attachments, then we send an error to the client
        if (outMsg.getAttachmentNames().isEmpty())
            {
            // use the super class method sendError to send an error to the client
            sendError(exchange, new Exception("Invalid answer from handler."), request, response);
            // and return
            return;
            }

        // get all attachment names from the out message
        Set set = outMsg.getAttachmentNames();
        Iterator iterator = set.iterator();
        String key = null;
        if (iterator.hasNext())
            {
            // we are now only interested in the first attachment
            key = iterator.next().toString();  // this resolves the key which is also the filename
            dh = outMsg.getAttachment(key); // this will resolve the data handler (file content)
            }
        else
            {
            sendError(exchange, new Exception("Invalid answer from handler."), request, response);
            return;
            }

        if (dh == null)
            {
            sendError(exchange, new Exception("Invalid answer from handler."), request, response);
            return;
            }

        // create a temporary file
        File f = File.createTempFile("tmp_", key);
        // open an output stream to this file
        FileOutputStream fos = new FileOutputStream(f);

        // now we use the FileUtil's copyInputStream method to copy the content of the data 
        // handlers data source into the output stream
        FileUtil.copyInputStream(dh.getDataSource().getInputStream(), fos);
        // and close the output stream afterwards
        fos.close();

        // now create a file data source with the temporary file
        FileDataSource fds = new FileDataSource(f);
        // create a stream datasource with the input stream of the file data source, the 
        // content type is provided by a method of the FileDataSource 
        StreamDataSource sds = new StreamDataSource(fds.getInputStream(), fds.getContentType()); 
        // then a new datahandler is created with the stream datasource
        DataHandler dhsds = new DataHandler(sds);

        // tells the response object to open a popup in the clients browser with the given 
        // filename (stored in key)
        response.setHeader("content-disposition", "attachment; filename=\"" + key + "\"");
        // set the content type to what the FileDataSource determined automatically
        response.setContentType(fds.getContentType());
        // also set the length of the content
        response.setContentLength((int)f.length());

        try
            {
            // now get the output stream of the servlet to send data to the clients browser
            ServletOutputStream sos = response.getOutputStream();
            // use the writeTo method of the data handler to easy to output of the data 
            // into the servlets output stream
            dhsds.writeTo(sos);
            // finally set the status of the response to OK
            response.setStatus(HttpServletResponse.SC_OK);
            }
        catch (Exception e)
            {
            logger.log(Level.WARNING, "Exception occurred" + e.getMessage(), e);
            }
        // afterwards clean up the temporary file
        f.deleteOnExit();
        }