UC-33e Problem

Hi !

Newly bought a UC-33e on disscount in my local music store but I can’t get it to work properly with cubase 6. It can controll instruments and audio faders but it will not controll the midi fader, and whenever I use it, it controlls the internal volume on the instrument that I’m curently playing too. Example : I move fader 1 wich is routed to stereo in but the instrument volume changes too.Then I move a non assigned fader and still the instrument volume changes(in fact every fader seems to react with the internal volume.

How can I make my instrument to not recieve from it and make the midi channels recieve ?