Solution : https://service.sap.com/sap/support/notes/634820 (SAP Service marketplace login required)
Key words : 
separate item partners, getwa_not_assigned dump occurs, download sales orders, stop entry occurs, error occurs, status = stop, sales transaction, sales order, crm server, saplcrm_download_btmbdoc_map program
Related Notes : 
       
| 641910 | Download to CRM: Dump GETWA_NOT_ASSIGNED (2) | 
| 621783 | Upload to R/3: Error in CRM: AM006 "Reference missing..." |