Create new workbook and new worksheet and close. Worksheet not sav

Hi,

I have scenario that users may give a filename and sheetname and both are
not exiting. So I will create workbook by

Workbook.SaveAs(newWorkbookFullFileName, Missing.Value, Missing.Value,
Missing.Value, Missing.Value, Missing.Value,
Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange, Missing.Value,
Missing.Value, Missing.Value, Missing.Value, Missing.Value);

and then sheet by

Sheet.SaveAs(worksheet.Workbook.Name, Missing.Value, Missing.Value,
Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value,
Missing.Value, Missing.Value);


After that, users may close the appliation and I will do:


if (!Workbook.Saved)
{
Workbook.Save();
}

Workbook.Close(true, Missing.Value, Missing.Value);
App.Quit();


But when I use Excel to check the content of the file, the sheet supposes to
be created as "SheetTest" is not there in the newly created workbook. Am I
missing anything?

Thanks
Patrick