PSE FX Import .NET is a solution which takes currency exchange rate information from the European Central Bank (or the authority of your choice) and injects it into your ERP system.
The system does all necessary cross rate calculations, even when you choose to override a rate. It also lets you decide which date to take the rate from (as far back as rates are available), and which date to use in the system (apply date).
http://www.pse.be/en/detail49.htm