How to generate password protected Excel file using BIRT?

Question

This is part of my code in eclipse to generate the Excel file. Based on BIRT.

if (ArrayUtils.contains(reportFormats, EXCEL)) {
    // set output options
    EXCELRenderOption options = new EXCELRenderOption();
    options.setOutputFormat("xls");
    options.setOutputFileName(reportName + ".xls");
    options.setSupportedImageFormats("PNG;GIF;JPG;BMP");
    renderTask.setRenderOption(options);
    renderTask.render();
}

I searched a lot on the internet, but cannot find the solution, please help. Thanks, everyone.