Quick excel question

Hi All -   I am trying to generate excel using xml. I have a scenario where only 7 columns  will be static and other columns are dynamic and may range from 1 to as many as  300 columns. And number of rows would be around 1000. What is the best approach  for this situation. I tried new cf9 spreadhsheet but it failed just for few  columns. XML workbook works fine where cf9 spreadsheet failed. I am just  wondering will using apache poi directly will be of any use since I think cf9  spreadhseet also uses poi

Thanks