Hi,
As far as i understand open PO means the quantity requested is not delivered completely.
If you look at datasource 2LIS_02_ITM closely then you will find the field ELIKZ which actually gives the information regarding the delivery status.
Map this field to 0COMP_DEL..Now if the indicator is X in it that means delivery is completed if not then its open.
So based on the same logic you can develop your reports.
Hope it helps.
Regards,
AL