capturing excise for STO PO

hi

We have created STO PO for bonded ware house to plant. In this PO we have entered Customs duty and CVD, and we have done MIRO for customs duty and CVD. After that i have selected J1EX capture invoice and STO PO number and given excise invoice number during that time system shows error message that invalid document. how to capture the excise invoice for STO PO.

govind.