As of SAP BW 3.5, you will have additional options to create variables for the following components of a currency conversion type:
Exchange rate type: The exchange rate type distinguishes between exchange rates that are valid in the same time frame, for example, the bid rate, ask rate or middle rate. The exchange rate types are stored and can be maintained in a central table (TCURV). Create a variable for the technical InfoObject 0RTYPE.
Target currency: The target currency can either be fixed in the translation type or not selected until the time of translation. Create a variable for the technical InfoObject 0CURRENCY.
Fixed time reference: If the time reference is fixed for a currency translation type, then the point in time for the exchange rate determination is independent of the data. The fixed point in time can either be a fixed key date that is stored in the translation type or can be determined using the system date when executing the currency translation. Create a variable for the technical InfoObject 0DATE.