Reply to Traktor pro 1.2 - filters

I'm trying to set up a low pass and hi-pass filter using a knob for each. But I can't figure out how to do this. I can make a knob into a filter, but the knob becomes both low pass and high pass i.e. it's neutral at the halfway point - this doesn't give the flexibilty or control I want.

I want one knob to start at 0 and gradually cut out the low frequences as I turn it up to 100. And the other knob to do the reverse.

I'm sure there is something quite simple I'm not doing - can someone point me in the right direction?