Printing different page heading for duplicate copy

Hi

I am using a ztcode for printing Returnable Gate Pass for a document no ( using smartform for layout ).

My requirement is -

when the Gate Pass is printed for the first time page header should be GATE PASS, and when it printed any time after that it should be GATE PASS DUPLICATE.

How to acheive this?

As this is not std tcode/program we cannot use NAST structure to check for printer flag. Also the spool request which is generated after print does not contain doc no as key...

Pls provide me solution.

Thanks & Regards

Harshada