Macintosh

ok so i can't seem to get my audio on my headset it keeps on broadcasting over the speakers.

options i have :

use system default
use default playback
use none

my logitech headset isn't popping up in the audio output device,
but it is popping up on the audio input device
I do however hear everyone perfectly if i use the speakers (default playback)

Talking on eve voice is also a no go, as the only thing ppl hear is static.
It isn't my headset as it is working just fine on teamspeak skype and other voice programs


I'm using a I-mac 27"
Processor 2,8 GHz Intel Core i7
memory 8 GB 1067 MHz DDR3
gfx ATI Radeon HD 4850 512 MB
Software Mac OS X Lion 10.7.2 (11C74)

Is there a fix for this issue or a workaround?
thx in advance