Populating AS/400 File


Our aim is to create a OW application to maintain a file on the AS/400. As the data items in the AS/400 file already exist in OW, but with differing attributes, JDE advised to create a table in OW with the fields having the same attributes as the AS/400 file but with different data items. Then to write the application to populate the OW file, but then, upon exiting the application,somehow call a table conversion to populate the AS/400 file from the OW table....
Any ideas on how we should call this table conversion from the Application....? - Or is there a better way of doing this...?!!!!
Cheers, Mike