how to update our reference and your reference field in PO

Hello Friends,

i need to create a PO in which i have to enter value in your reference and our reference field in communication tab.

i m creating PO through Bapi BAPI_PO_CREATE1.

after i created the PO through bapi, user is asking for entering value given by him in YOUR REF FIELD

and in OUR refrence field the PO created...

how i can fulfill this requirement, please reply.