Since the bitcoin is highly recommended by the online trading companies just like "traderush online" and "eztrader demo", its easy for all bitcoin holders to trade currencies with bitcoin both as a deposit and withdraw method and as a currency.
Again,
1. You can open Eztrader demo account with bitcoins and deposit bitcoins to your wallet, in order to trade USD\EUR , NZD\AUD and others.
2. You can trade USD\BTC and BTC\EUR
Of course, you can combine and do both.
Good luck.
Can you repeat that in English? Or someone translate for me?