Credit card mapping details and Credit card supplier setup

Hi, 

We are implementing PeopleSoft Expense for our client. They have provided credit cards to all employees but they dont use the concept of Per diem. For Credit card mapping, is the Expense location, Country code and currency code mapping important?

If so, is there a standard source from which we can get the Expense Location, Country code and Currency code mapping for PeopleSoft Expense?

Another question, as per Peoplebooks, AMEX Supplier should have the naming as AMEX. But what if we have two credit cards from two different banks but both provide AMEX credit cards? How should these 2 suppliers be configured in the system. To be precise the naming convention.