How to add Sub Report to Group Footer in Pentaho Report Designer

Hi,

My requirement is i need to get the sub report after the main report for an employee as i am doing grouping on employee number.

So i have tried to add sub report in the group footer to get sub report after main report employee wise.

But sub report is not displaying in the report after generating.

Please help me in this...How i can add the sub report to the group header so that i can get the sub report following the main report.

Thanks in Advance.