Add PO in SO Document Flow

Hi

I created SO using BAPI and PO also creaed with BAPI with multiple purchase contracts. While creating PO I did not pass the Purchasing requestion. If I pass Purchase ing Requisiton with PO Bapi, I am unable to create PO. So, I did not pass the Purchasing Requesition with PO Bapi. Now I am not getting the PO in SO document flow.

Is there any FM to update to add PO in SO document flow. I tried several FM, but could not success. I am able to update only VBFA, but could not get the PO in SO document flow.

Are there any FMs to update hte PO in SO document flow.

Thanks in advance for your inputs.

Sai