Currency by payment

[kutsu]

I'm offering options to pay by credit card and money order.

I would like to make osc to do following:

 

at the checkout_payment.php

 

If customer choose to pay by credit card, automatically recalculate to USD.

If customer choose to pay by money order, automatically recalcluate to JPY.

 

It does not have to use java script to recalculate on click but next page.

Any informaiton I would very appreciate!