our company is raising an invoice to another co. in USD currency.total amt is 20000 USD inclusive of service tax. now the payment will be made by the other co.by next month.we will post the entry in our co.'s accounts at todays dollar rate and payment will be in a different dollar rate, so what will be the treatment of difference of dollar rate in our co's books of accounts.and we will be liable to pay service tax according to todays dollar rate and if there is an increase in dollar rate next month so shall we be liable to pay extra service tax recovered. pls help meeeeee