Export to excel not working with #cspan

The code I use for exporting my grid to excel is as follows :
Pls note that I am not using
mygrid2.toExcel(“http://dhtmlxgrid.appspot.com/export/excel”);
because I dont want data to be sent to an external server.



var mygrid2;
function doInitGrid(){
mygrid2 = new dhtmlXGridObject(‘mygrid_container2’);
mygrid2.setImagePath(“codebase/imgs/”);
mygrid2.setHeader(“Excel ID,Uploaded Date”);
mygrid2.attachHeader("#select_filter,#select_filter");

mygrid2.init();
mygrid2.loadXML(" …");
}
window.onload =doInitGrid;

However when I add headers in this format , export doesnt work :-
mygrid2.setHeader(“Report Information,#cspan”);
mygrid2.attachHeader(“Excel ID,Uploaded Date”);

Could you pls tell me how to do this?