@dorandoran
Actually, I already tried those codes.
After series of trying I ended up doing only one worksheet on Excel 2000. The problem with most of the samples is that it is for Excel 2003 and beyond. Excel 2000 does not fully support xml that's why it cannot create multiple work sheets via xml. There is one way to this if I try to install the excel on the server and use the Microsoft Excel com object. But that will not suit my application and will only cause my app to become slower.
My solution back to xml with only one worksheet.