Stamping PDF files in the ECL Viewer

Dear All, I have a problem that i can't write a stamp text on the PDF files in ECL Viewer, it works with all original types like dwg,dxf,jpg,gif,bmp,... except pdf.

I am using the method SHOW_DOC_META_DATA in the badi defination DOCUMENT_ECL01.

Here is my code, Please Advise.

Thanks

METHOD if_ex_document_ecl01~show_doc_meta_data.

DATA: BEGIN OF line,

a(20) TYPE c,

v(50) TYPE c,

END OF line.

• Adjusting Viewer Settings

y_position = 35.

x_position = 25.

font = 'Arial'.

size = 1.

color = 255.

transparent = 'X'.

• Printing Line#1

line-a = 'Document#'.

line-v = 'Test'.

INSERT line INTO meta_data INDEX 1."Here is the problem

ENDMETHOD.