CDHDR & CDPOS tables are not updated properly when I create a PO line Item

Hi Friends,

I have a requirement where I need to track the PO line items creation dates(Not change date). When I create a PO line Item,it is updating in CDHDR & CDPOS tables but Item number is showing as 00000 for all the Items,it is not updating properly.

Please let me know how to get the Item number when it creates.