Authorize.Net CIM: How do currencies work?

Authorize.Net only supports one currency per Authorize.Net account. Magento supports currency conversion, but all transactions are processed in Magento’s configured ‘base currency’. The base currency and product prices can be set either globally or on a per-website basis.

This means two things:

1. Your Magento base currency must match your Authorize.Net account currency. These are configured outside of our payment extension settings. If they do not match, all of your transactions amounts will be incorrect.
2. It is possible to run multiple base currencies (setting prices explicitly, rather than being automatically converted), but each currency must have its own website and its own Authorize.Net account.