nvmixer: "create LFE channel" greyed out

[Florian Schroeck]

Hi,

i've got a 5.1 speaker system and I'm using the onboard sound of my Asus 
A7N8X. The Nvidia driver has a feature to upmix stereo sound. This works 
fine, except the button for creating a LFE channel is greyed out *hmpf*.
I'm using Warty and the latest updates, also of the Nvidia driver.

Btw, under WinXP *pls have mercy :>* this works.
Any ideas?

A stereo to 5.1 upmix plugin for Beep Media Player would also be good.

Thanks&bye,
Florian