Solution : https://service.sap.com/sap/support/notes/144016 (SAP Service marketplace login required)
Key words : 
paobjnr        rkeobjnrsupkz          supkz                  <--insertvbeln          vbeln insert, delta          char1abdis          abdiskwmeng_org    kwmeng double-click, additional key words sd/copa, import parameter erkrs = 's001' press, kwmeng_org     kwmeng double-click, function library initial screen, insert field supkz, delta          char1 save, function module copa_sd_document_item_create, enter function module
Related Notes : 
       
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| 212472 | CO-PA Incorrect update for scheduling agreement | 
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| 81335 | Incoming order for sched. agreements not correct |