VIN Number and Serial Numbers

Hi all,

Just wanting to confirm my solution in that I am receiving a file to create Orders ( IDOC MESSAGE TYPE ORDERS05)

I want to hold the the vehicle identification number VIN and serial number.  Also is it best to get these 2 fields populated via IDOC or should I get entered them in the sales order? If the answer is in sales order than which are the best Fields to use in VBAK.

Or can I have these fields populated in ORDERS05?  I wasn't able to locate the fields in ORDERS05

Please remember I need these 2 fields passed through to the Purchase order and Invoice. Both VIN NUMBER and serial number.

Thanks