In this configuration transaction you are able to define translation ration for each pair of currencies. Despite two currencies are exchanged 1:1, it will be necessary to be added.
IMG Path: SAP NetWeaver -> General Settings -> Currencies -> Define Translation Ratios for Currency Translation
When you open the transaction you will be prompted that any changes of already defined ratios could result in inconsistencies.
When you continue with the transaction for new entry, click on the related button.
Fill the necessary fields and click on save.