We hedge foreign currency transactions (i.e. buy currency in advance so the exchange rate is fixed at a particular value for a particulr contract and/or customer, etc) so need to be able to specify the exchange rate on all invoice and payment transactions. In particular, the OData entity has a Exchange Rate field, but it is not possible to use it except in legal entities in a limited set of countries; even in the those countries, the functionality is limited. Also, there does not seem to be a way to override the Exchange Rate from the UI. Please extend the exchange rate handling to allow it to be specified for all invoices and journals independently of the current default rate.