Unfortunately this feature hasn't made it through to BlackBerry 10 which is a real shame. Especially as the additional currency keys are on the second symbol screen. It can be quite arduous to switch constantly between the numbers keypad and the additional symbols.
Luckily, there's a very simple way to grab a different currency symbol. If you press and hold on the $ key, a popup will appear of the additional symbols. Slide your thumb onto your desired currency and then let go. This means that you don't have to switch back and forth whenever you want to use a different currency.