About base currency and customer currency.

In the Invoice, I would like to the base currency for all items, sub total and total amount. And show a additional customer currency in the final total amount. Also, show the exchange rate.

For example:

Item #              
1                                              100
2                                              110
3                                              200
                                sub toal    410
                                Total: HKD410
                                Total: CNY328   ***Customer Currency*** Exchange Rate 1HKD=0.8CNY