i searched on the soundblaster forum for an answer but coudn't find it.

i recently bought an soundblaster xf-i elite pro and it worked fine i'm happy with it.
the only thing is the headphone volume, i can't change it.
it's always loud when using adobe audition.
there's a master volume on the right side of the box and the headphone on the left.
i tought i can change the volume with the regulator on the right but it won't work?
is there more to install except the sound card drivers?