USB headphone + microphone

[Nigel Ridley]

I checked the archives but couldn't find anything useful. I also Googled but also came up with a 
blank.

How does one get a USB headphone set to work under Kubuntu (10.04)?

When I plug it in and then open Kmix it gives options for the headphone set and I can hear my own 
voice through the headphones via the microphone but not any audio from the laptop. If I play a 
music file or any other multi-media file the sound only comes out of the built-in speakers.

There is no problem using regular 3.5 jack plug headphones.