Hi,
I have checked the document you putting Demand against a WBS & also raising the sales order against WBS.
I have never tried this kind of scenario but you can try like this Individual & collective indicator as 2.
If that didn't work than try for Strategy 61 or 60
For that you have to create a planning material mention it in MRP 3 view
than create demand of planning material & raise the sales order Finished material.
it is consume the requirement & it will appear in MD73 Report.
Thanks & Regards
Sandeep Kumar Praharaj