Duplex not working

I can not seem to get duplex working.

I have tried setting duplex on the printer, I get only single pages.

I tried creating a custom printer and changing the settings using the following code

 

 procedure TPDFViewerMainForm.PrintWithDialog(asPrintJobTitle: string = 'ExitCare Print Job');
var
  iPrintOptions: integer;
  iPrintFrom: integer;
  iPrintTo: integer;
  SPrinterName:String;
begin
  PrintDialog.MaxPage := iTotalPages;
  PrintDialog.MinPage := 1;
  printDialog.FromPage := 1;
  printDialog.ToPage := iTotalPages;

  if PrintDialog.Execute then
    begin
      iPrintOptions := PDFFile.PrintOptions(0, 0, 'ExitCare Print Job');
      if PrintDialog.PrintRange = prAllpages then
        begin
          iPrintFrom := 1;
          iPrintTo := iTotalPages;
        end
      else
        begin
          iPrintFrom := printDialog.FromPage;
          iPrintTo := printDialog.ToPage;
        end;
        SPrinterName:=PDFFIle.NewCustomPrinter(Printer.Printers[Printer.PrinterIndex]);
       PDFFIle.SetupCustomPrinter(SPrinterName,7,3);

      PDFFile.PrintDocument(SPrinterName, iPrintFrom, iPrintTo, iPrintOptions);
    end;
end;

Still only get single pages. Nothing I have tried seems to print in duplex mode. I have tested the same PDF in both Adobe Reader and Gnostice and they print in duplex fine.

 

I am testing using the 7.16 beta, but this also happend in 7.15.

 

Thanks

Bern