Solution is easy after the magic line that exports the file as ms-excel xls mime format thingy you add the content disposition line.
Print "Content-Type:application/vnd.ms-excel"
Print "Content-disposition: filename=Ninja_Report_" & Day(Today) & "-" & month(Today) & "-" & year(Today) & ".xls"
Super.
Works well with:http://www.notesninjas.com/A555F9/nn.nsf/ByAlias/WebExcelExport