Hi Vijay,
Order sent and order reached to vendor are two separate state / transactions.
you can create 2 scenarios -
1. order Idoc to file - here you can use two operation mappings with maintain order at runtime.
the first map will send the file to target. second map will update the z table with status sent. using MORT will ensure the table will be updated only when the order is sent.
2. file to RFC - this will be called when order is successfully reached. this will be mapped to a rfc and update the table with "order successfully reached" with PO number..
Thanks
Sugata B