Query: how to manage Openitem accounting in eProcurement requisition

we have a requirement where User needs to enter OpenItem accounting information in eProcurement Requisition distribution level.

Once requisition is approved and sourced to PO, Openitem information has to get populated in PO distribution 

When voucher is created using Copy PO, Open item information has to be populated from PO distribution. 

Does anyone has idea on about the delivered process what we have on Openitem in eProcurement requisition ?

Thanks

Kalyan