Automatic - Updation of Business area in vendor line item

Dear Experts

                      we have one issue with automatic posting , we are still in classical G/L . For Travel expense  posting we are using IDOC ,and entry would be

Vendor CR

Expense Cr

ISSUE

trough Cost center in expense line item business area get updated automatically.   But in vendor line item business are is a mandatory field for us.

kindly let me know is there any BADI or BTE  available for updating business are in Vendor line item

Regards.

Ajeesh.s