Heading for downloaded file(.txt file)

Hi Experts,

I'm downloading data from internal table to presentation server using

CL_GUI_FRONTEND_SERVICES=>GUI_DOWNLOAD. and data seperated by tab delimited.

Now i want to provide for those columns headings .

EX:-    i have 3 fields like MATNR , MTART, WERKS, LGORT and having 3 records in ITAB.

I want download data as below.

output:    MATNR        MTART     WERKS     LGORT 

              1234           FERT        5201       0001

              5678           FERT        5201       0001

                 13579           HALB        5201       0001

please help me.. i wan data exctly under the heading.

Thank you.

Regards,

Balaji.