Solution : https://service.sap.com/sap/support/notes/617221 (SAP Service marketplace login required)
Key words : 
attached source code corrections, additional kna1 fields, additional fields, crm server, transaction pide, customer data, longer apply, data exchange, user exits, mentioned notes
Related Notes : 
       
| 720720 | Exit DE_BCS2S: No Delta Download of customer-specific fields | 
| 634869 | SAPKU40001: Support Package 01 for CRM 4.0 | 
| 529920 | KNA1 fields not contained in CRM BP data model | 
| 513313 | Sls office and sls group not contained in CRM BP data model |