bwin is using the concept of Tournament Euros (T€). If you win multiple entries to tournaments, any extra entries will be exchanged for Tournament Euros which you can use to buy-in to any Real Money Scheduled or Sit & Go Tournament (except Heads-Up STT).
You can check your Tournament Euro balance any time by going to the My Poker page under the Account section.
If you don't have enough Tournament Euros in your account to enter your chosen tournament, the buy-in window of the tournament will display a combination of your Tournament Euros and regular Euros. You can also elect whether to deplete Tournament Euros first or regular Euros first when buying into a tournament - this can be set in the Preferences section in the client.