Export Button in OAF Page, record fetching issue

I have created a export button on OAF Page.(Id, Prompt, View Instance)

But header level are not captured.

E.g

Level 1 Header :Planned

Level 2 Header: Activity1     Activity2   

Data:                 Sep-15          Sep-15

                         Oct-15          Oct-15

                         Dec-15         Dec-15

While exporting data, Level 2 header and data columns are exported, but level 1 header is not exported.

Is it possible to Capture the Level 1 Header?

Regards,

Suraj Chandak