How to enable crossover frequency for SW?

Hope it's put right in here.

Explanation first:

I own a 'Teufel Concept E Magnum' - 5.1 System, put behind a Soundblaster
Audigy 2 and normally i am supposed to set a crossover frequency for the sub
in the settings found in Creatives' Speaker controls.

But they aren't (yet?) available under the Vista-drivers and poor me
couldn't get a bit of bass out of the sub.

Maybe i just didnt find a way to get this working...so is there anyone with
a kind of tip or trick?
Is it even possible to use all this EAX-thingies (Media source and so on)
under Vista?
Just didn't dare to try to install it yet.