"Default Language Currency" Issue

[beadedlily]

Desired Outcome: Customers are able to select the currency of their choice for shopping but at checkout the cart automatically switches to the default currency. In this way it serves as a handy tool for the customer but my reports and order totals are all in my local currency.

I assumed that this was the purpose of the "Switch to Default Language Currency" option. However, all it seems to do is force the customer to switch back to the default at every turn. If I'm doing this properly, (Always a BIG if) what exactly is the purpose of this option? If it's going to switch back automatically, why not just remove all currencies except the default?

One thing, however; because I am in Italy and my local currency is the Euro but my site language is English, (American) I altered the
shop/includes/languages/template_custom/english.php define Language_Currency to EUR.

Could this be mucking things up?
Or maybe I'm spinning my wheels and there is a simple solution to this staring me in the face that I just can't see?

Any and all help or suggestions would be appreciated.

[beadedlily]

What would be even better is if my copy of the invoice and the customers copy showed order totals in both the default and customer-selected currencies. Is this possible?