Enhancement for ksb5

HI all,

I need to do replace fieds for report run trough tcode ksb5.it is an controlling document.

my requirement is - after the report is displayed we can see unit and quantity fields,those where picked from ekpo table,but i need unit and quantity from esll table.which are enterd in services tab in PO.how to do.please explain me in detais.points are awarded for all helpful replies.thank you