Hi,
1. Create a virtual storage loc in plant A.
2. Transfer the goods to the virtual storage loc from plant B using any stock transfer method (301 or STO),
3. If the BOM exists and you want subcontract scenario, create a subcontract PO to the vendor (plant B) with the main component. Issue the subcomponents from the virtual storage location to vendor (plant B) with respect to PO. Maintain "free" indicator in PO if its FOC.
4. Do GR for the subcontract PO to the new virtual storage loc. Now, physically stock is in plant B, but virtually (in SAP), its in plant A, virtual storage loc.
5. Maintain the correct shipping point (that is shipping point of plant B) to the virtual storage loc and plant combination.
6. Create Sales order in plant A and deliver the goods from plant A, virtual storage loc. In this case, physically you will be delivering from plant B, but in SAP, it will be from plant A.
Alternatively, refer the document, which may give you some idea: Third-Party Subcontracting using SC Vendor Concept
But may I know why you are transferring to plant A virtually only and follow complicated and odd business process?????
Regards,
AKPT