Generate SSRS report PDF file automatically in AX 2009

Remark: The AOS service running user can't be 'Network Service'(The default value), or else the web request will be deny running in batch job.

static void Jinn_GeneralSSRSPDFByCode(Args _args)
{
    System.Net.WebRequest       request;
    System.Net.WebResponse      response;
    System.IO.Stream            stream;
    System.IO.FileStream        fileStream;
    System.Byte[]               buffer = new System.Byte[1024]();
    
    str                         m_URL      = @"http://******/ReportServer/Pages/ReportViewer.aspx?%2fDynamics

%2fCustSalesOrderReportSRS.CustSalesConfirmSRS.RDS&rs:Command=Render&rs:Format=pdf";
    str                         m_FileName = @"\\****\MailAttachment\SalesConfirmation.pdf";
    int                         m_ByteRead;
    ;
    
    request = System.Net.WebRequest::Create(m_URL);
    request.set_Credentials(System.Net.CredentialCache::get_DefaultNetworkCredentials());
    
    response = request.GetResponse();
    stream   = response.GetResponseStream();
    
    fileStream = new System.IO.FileStream(m_FileName, System.IO.FileMode::Create);

    m_ByteRead = stream.Read(buffer, 0, buffer.get_Length());
    while (m_ByteRead)
    {
        fileStream.Write(buffer, 0, m_ByteRead);
        
        m_ByteRead = stream.Read(buffer, 0, buffer.get_Length());
    }
    
    fileStream.Close();
}