How can you accept multi-currency online payments into one merchant account?

Many online card processing companies offer global payments. The one that instantly comes to mind is Braintree (company).

They offer payments in the following currencies: http://www.braintreepayments.com...

There are others like Worldpay (www.worldpay.com) that also accept international payments in other currencies: http://www.worldpay.com/support/...