New Post: Landscape does not change

IWorkbook wb = new XSSFWorkbook(stream);
                ISheet sheet = wb.CreateSheet("Sitrep");

                sheet.PrintSetup.Landscape = true;
                sheet.PrintSetup.PaperSize = 9;
                sheet.PrintSetup.Landscape = true;
                sheet.PrintSetup.FitHeight = 0;
                sheet.PrintSetup.FitWidth = 1;
                sheet.PrintSetup.Scale = 100;