Thanks both, for your infromations.
Honestly, i checked out allready many Forums and Creative Pages and the whole stuff. I m wondering, if i configured FF once with :settings and added something.
However,

Fact 1, sgunhouse, sorry : its not that easy. Belive me, i m working as an support, so i checked this out.

Fact 2, lando242, you're right: its not an Opera fault, and it seems not configured yet.
Question is : HOW do i configure my Rear channel, like a front channel. Isn't that possible? I mean that there are other soundcards (and software), that are possible to play any Sound on any channel. They are smart enough, to even check if its an HEadset or Speakers. So, this program (i guess realtek?! maybe?!?) asked (if you pluged in "wrong") which source do you want to hear, or what do you pluged in, and it gives you the right signal. Is there a Program?

I mean, sorry if this forum doesnt fit for this questions... but anyway... have a try

(In time i solved it, with connecting my onboard Sound and my Soundcard, just switching between "standard" Audio Device / Gamning/Headset -- Speakers)