Exchange rate not reflecting in PO created thru bapi for foreign currency!

hi friends,

am creating PO thru BAPI_PO_CREATE1...in the input file, i have given currency as USD and Exchange rate as 0.5, but in the created PO, i am able to see only 1 as the exchange rate...i even tried changing it using BAPI_PO_CHANGE, but no luck..but in case of local currency, which is EUR, am able to translate from the file whatever the value as exchange rate of the PO...this problem only comes if it's a foreign currency..am i missing something? pl advice

Regards,

Muthu