SAPscript download from ITS

Hi,

I'm using following code in a transaction to download a sapscript form to frontend and it is working fine - but when I call the same transaction in a function module from ITS the form is not downloaded.

CALL METHOD lcl_cls->gui_download

EXPORTING

bin_filesize = v_size

filename = v_name

filetype = c_bin

CHANGING

data_tab = i_content_bin.

where lcl_cls refers to class cl_gui_frontend_services.

What could be the reason for this. Do I need to pass some other parameters in method gui_download?

Regards.

Vishwas Madhuvarshi.