[Windows 7 - Creative Sound Blaster X-Fi] External Soundcard Problem

What do I use?<<

Windows 7 Ultimate, Creative Soundblaster X-Fi (http://www.amazon.de/Creative-SoundBlaster-Surround-Soundkarte-extern/dp/B0019JDDC8), Philips subwoofer and 2 non-philips related speaker

What kind of problem do I experience?<<

First, I had no sound from my subwoofer. Updated the driver, then everything worked perfect (besides, when I started my computer the standard audio hardware switched to another speaker) when I played a MP3 through MPC/Winamp/Musicbee/etc. However, when I started to play videos on MPC/VLC Player I only got sound from the subwoofer?! Then I did something on the settings and I'm back at hearing only through the two speakers again.

What do I want?<<

Please help me to fix my sound, so that it starts working when I start up windows, with audio and video, so that I can watch the newest JAV releases with 5.1 sound.

What did I already do to fix the problem?<<

Installed the newest driver. Played around with the audio cables, turns out everything is plugged right inside the external soundcard and it seems more of a software problem. Did tests via the audio manager and everything fucking works BESIDES WHEN I NEED IT TO WORK.