Many currencies, two payment gateways

Hello, when I have 2 currencies the system works well. But when I add other currencies , the currency convertion system enters in a loop.
Probably I am doing something wrong.
In my site I have to payment gateways: Paypal and Mercado Pago.
Paypal : USD
Mercado Pago: ARS$
When I add Yens (for example): the buyer buys in yens and in the checkout sees USD so then changes the currency to Yens, the page enters a loop. (paying trough Paypal).
How can I do so that the person buying in Yens sees the checkout page in Yens, but I receive dollars in my Paypal account?
Do you have any configuration tutorial or guide?
Now I have deactivated other currencies because i want the site to work well because I am launching my shop next week. But it would be awesome if I could solve this.