ME59n exit/BADI to copy purchase requisition custom field to purchase order

I have added a custom field (Unloading Point) in the Purchase requisition customer screen. Now When a purchase order is created from the purchase requisition through t-code ME59N, I need to copy the unloading point value from the PR to Unloading Point in the shipping tab of the Purchase Order. Whch User-exit/BADI can be used for this purpose. <removed by moderator>

Edited by: Thomas Zloch on Nov 23, 2010 12:44 PM - please do not offer ...