service tax on invoice raised in foreign ciurrency

We are providing the service to foreign party but the invoice will be addressed to indian office. The scanned invoice will be send by them to foreign party.

Please tell me whether the service tax @ 12.24% could be added in the bill amount in Foreign Currency
i e USD or JPY etc ? and also tell me whether they deduct the tds and what rate -

whether there is any issue regarding service tax ?