Link between Picking List items & Purchase Order No. (URGENT)

Hi All,

I have a interesting issue at hand. I would like to know if i can maintain the link of a material with the Purchase Order No. with which it was procured from. I know once the MRP run is done, the Materials create a requirement & this then is converted to a PO, then the PO is received (Mvt - 101).

The challenging part is once the Picking List (CO27) is generated & the items are kitted to the shop floor (Mvt 261), the link between the material & its PO No. is lost. Is there anyway i can continue this link. In the picking list, can i enter the PO No.? I see a column titled Purchasing Document, but not sure from where the data to this field is being read. If someone can map this link for me, would be highly appreciated. Look forward to your ideas on this issue.

Vivek