Purchase Requisition field is mandatory in ME21N T-code How to upload excel file in ME21N T-Code

Hi Experts,

I have done one enhancement(BADI) in ME21N T-code( Purchase Inquisition filed is mandatory in ME21N T-code). Now I have to upload excel file in ME21N T-code. I have used BAPI_PO_CREATE when i call this function module one error message i am getting 'Please enter the Purchase requisition filed'. How i can upload with out mandatory field in ME21N T-code. I am using BAPI_PO_CREATE1 also i am getting error. Please send me a sample program.