Setting the paper size in Delphi for a endless label: Brother Printer QL 550

In Delphi I can set the paper size of a label Printer (see code below). But I can't set the paper size in the Brother QL 550 when the Label is endless.

So if I have labels 38mm x 90mm the procedure works well. When I have a endless label I get a error from the Brother Printing Driver saying the the label is endless and not compatible.






***********************************************************************
    Printer.GetPrinter(Device, Driver, Port, DeviceMode);
    OpenPrinter(Device, hPrinter, nil);
    try
      DevMode := PDevMode(GlobalLock(DeviceMode));
      try
        with DevMode^ do
        begin
          dmFields := dmFields or DM_PAPERSIZE;
          dmPaperSize := DMPAPER_USER;
          dmFields := dmFields or DM_PAPERWIDTH;
          dmPaperWidth := 380; //  39 mm : in 1/ 10 mm;
          dmFields := dmFields or DM_PAPERLENGTH;
          dmPaperLength := 900; // 90 mm : in 1/ 10 mm
          ResetDC(Printer.Handle, DevMode^);
        end;
      finally
        GlobalUnlock(DeviceMode);
      end;
    finally
      ClosePrinter(hPrinter);
    end;