dont have a whiteline but i installed a cusco. My cusco came with extra hardware to lower the ac line but this can still be done with out it.
you need to unbolt the bracked that holds it to the car near the drivers side. it should be bolted on there with two screws, (it might help to take off the clamp that holds the hose first)
unbolt these two screws and move the line down gently (you wont break it at all, just dont be to rough on it) bolt the bracket back in using one bolt placing the top of the braket in the bottom hole. Reconnect the hose to the clamp so the hose is secure. Now you may just have to pull the ac line towards the front of the car and down slightly, this should give you enough clearance.
good luck.
Pat