Solution : https://service.sap.com/sap/support/notes/550053 (SAP Service marketplace login required)
Key words : 
higher-level organizational units, responsible purchasing group, proposed item, purchasing organization, determined correctly, terms bbppu05, rhga_read_tree_up_set reason, internal buffering, solution import, attached patch
Related Notes : 
       
| 675826 | SP08 Notes for EBP 3.5 | 
| 620955 | Support Package 07 notes for EBP 3.5 | 
| 597764 | Support Package 06, notes for EBP 3.5 | 
| 575041 | SP05 notes for EBP 3.5 | 
| 574952 | SP04 / SR 1 - Notes for EBP 3.5 | 
| 553906 | R/3 SP03 Notes for EBP 3.5 | 
| 547725 | Support Package 03 for SRM 2.0 | 
| 110909 | Composite SAP note on generic attributes |