screen exit in purchase order MM06E005

Dear Experts.

I have implemented a USER EXIT (MM06E005) to tcode ME21N at header level (Add new tab and one field in it) and respective field getting updated in the table EKKO.

But my problem is that field is not display at ME23N transaction.

So please give me some idea or some code to solve this problem.

Good answers will be rewarded.

This was the suggestion given in earlier thread.

If sy-tcode = '<TCODE>'.

loop at screen.

if screen-name = <FIELDNAME>.

screen-input = '0'.

modify screen.

endloop.

endif.

I have tried using this piece of coding also, but still it is not working. Plz help me in this regard. Its very urgent.

Valid points are suitably rewarded.

thks in advance,

nagarajan