go to the tool bar up top and find preferences (I think its called). Then click the tab for Audio. In there you will find which interface you are using. More than likely your default soundcard will be selected. Just select the behringer and you should be good to go. I use 7, so individual track/input selection is possible. I don't think 6 does that.
Its not hard to setup.
And before you move on to more acid programs. It doesn't work well with some plug ins. I'ld start looking into a differenct type of software. I've been using it for years and have worked my own system out. But acid just does some annoying stuff sometimes.
