How to auto populate screen field in standard transaction?

Hi,

I have a business requirement to auto populate a screen field while saving the transaction 'QA11'.

I tried populating the field in PAI of that screen,but the FIELD - MODULES ON INPUT / ON REQUEST are not getting executed with my manual population of the field.

How to make them execute?

And addition to that,there is no parameter id to that screen field to which i can set the value.

Any help is appreciated.

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Thank u.

Santosh

Edited by: Thomas Zloch on Oct 25, 2011 1:38 PM