Solution : https://service.sap.com/sap/support/notes/498032 (SAP Service marketplace login required)
Key words :
solution fill sales office, delete update flags sales_grp, function module crm_salesdoc_map_mbdoc2bapi, badi crm_dataexchg_badi implemented, function module crm_r3_salesdocument_upload, changed sales order, sales order reason, fields 'sales office', leading crm server, update flags