Virtualbox audio problems

[abexs]

I'm using Ubuntu 10.10 and installed Oracle Virtual Box (not the open source edition) + Guest additions.
The guest OS (Win7) doesn't find any audio-input card or audio device.
I tried every combination of audio drivers.
Who has the solution?

[xxs2010]

I think it's the problem of Win7. When I installed Win7 last year, I can't find the audio device, too. My solution is open the Realtek, and click the folder locates in the right-up, the tick both items, reboot.
Hope it may help you.

[abexs]

Where do I find "the Realtek"?