WS_DELIEVRY_UPDATE Stopping Auto GR

Dear All,

I am having a peculiar scenario where I am posting Goods Receipts from MIGO and bypassing it with my custom program based on a business scenario ( Replenishment Stock Transfer ).

In the custom program, I am checking whether open delivery exists, if yes then Post the Goods Issues using FM WS_DELIVERY_UPDATE. This FM is performing Picking, PGI, and GR. Business wants to restrict this GR inspite of the setting being set as one step posting ( Table T161W, where the Field step is mentioned as One step ) in the System and wants System to act according to the setting maintained in the maintainable custom table ( one-step or two-step posting). I am unable to find what should I pass to FM to stop Automatic GR.

    CALL FUNCTION 'WS_DELIVERY_UPDATE'
      EXPORTING
        vbkok_wa                 = ls_vbkok
        synchron                 = 'X'
        no_messages_update       = ' '
        commit                   = ''
        delivery                 = delv_no
        update_picking           = gv_picking_todo
        nicht_sperren            = 'X'
        if_database_update       = '1'
        if_error_messages_send_0 = 'X'
      TABLES
        vbpok_tab                = lt_vbpok_tab
        prot                     = lt_prott

All help and suggestion are welcome.

Looking forward to hear from you all.

Thanks in advance.

Regards,

Reshu