How to get Purchase Orders in WBS element

Hi hope you can help me out! i currently have a project on capital expenditures. I need to get the Purchase Order (PO) numbers of the WBS elements that I have. I only have the following data with me though:

Asset ID, WBS element, and Project number

I cannot use tables EKKN and EKPO because I dont have the purchasing documents. I tried CN41 and couldnt find any.

thanks in advance!