I think the VUK will shoot the ball into the trunk. The trunk will then rotate and shoot it up the entrance of the mansion. After that, the roof of the mansion will explode, and 6 balls will be shot to the ramps, and there'll be smoke coming out of the mouths of the gargoyles.
I'm pretty sure that's what will happen , though it could also be that the VUK just shoots the ball towards the targets, maybe the target-inserts lights change position and you have to time your shot with the lockbar button.