Hi
I hope below mention link and sap note will help to solve your issue
http://wiki.sdn.sap.com/wiki/display/CRM/Enhancing+the+CRM+Middleware+Example
http://wiki.sdn.sap.com/wiki/display/CRM/Enhancing+the+CRM+Middleware+Example2
Note 833585 - CRM EEW Using the BP enhancement in the ERP customer master
Note 736595 - Exchange of EEW fields with R/3 customer master
Note 864222 - Composite SAP note on the data exchange of EEW enhancements
Note 831536 - Swapping EEW enhancements between CRM and ERP
Note 863611 - Exchanging company code data with ERP
Note 529920 - KNA1 fields not contained in CRM BP data model
Regards,
Vaibhav Shah