How can a business accept payments in multiple currencies into a single 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/...