x-fi rear speaker volume !!

[henryford]

got a x-fi sound card running logitech 5-1 speakers. the rear speakers are about 1.5 - 2mts behind me with the fronts on the p.c. desk. when i am gaming i can not hear the rears although they are working o.k. there is no front / rear fader on the speaker set up and i cant find any in the creative x-fi software.... any idea's