Marketpress currency error

One of the sellers on my site had a problem with conflicting currencies in a recent transaction. She is in Europe and the buyer was in the US. Because of there being no automatic currency converter, she changed her prices manually into USD but it doesn't seem to have worked properly. She sent me this message.

"I made a custom order and had it listed in USD (I changed all listings from EUR to USD for now). When her payment came through form Paypal, I noticed it was in EUR. So, the order total was 23,60 USD with shipping but she was charged 23,60 EUR. There must be a glitch somewhere, since it still shows the price in USD in my Manage orders site."

You can see it in the attached screenshot.

Is there a setting somewhere she has missed, that would fix it for now?

Even if there is, I'm thinking this is a pretty serious bug that it is possible to set it this way.

Thanks