extraction of purchase order condition data

Hello all-

I do see that SAP has delievered the 2LIS_11_VAKON infosource which as by sales order the conditions within that sales order per item. However, I need to get similar information from the purchasing side. Ideally, I would like to get by purchase order the conditions per item too. I however do not see a standard extractor from the purchasing side to get this done. Any idea on how to pull this data into BW from the purchasing perspective to get the needed relationships? Any ideas would be greatly appreciated.

Thanks.

Dan