Separating operation flashpoint and teamspeak sound

hi.

i am using integrated sound card on a dfi infinity nf4 motherboard,
AC97 i believe its called.
i have problem with my sound setup. my sound channel in operation
flashpoint isnt separated from main volume in widnows. when i enter
game and lower audio volume in game (Effects, Radio, Music) my "Wave"
volume also lowers in Volume control and that, of course, also effects
sound volume in teamspeak so I cant have optimal sound volume in game
and teamspak, therefore cant understand my teammates.

I've set up my audio settings in windows to work in 5.1 channel mode,
but i have headset connected to my onboard sound card. what do i have
to do in order to separate Operation flashpoint sound channel from my
main volume in windows so i can lower my volume in game with no effect
on main windows volume (and teamspeak)?