Animation easing type can't be changed dynamically

import Qt 4.6

Rectangle {
    id: animatorBug
    width: 500
    height: 200

    Text {
        id: label
        x: 0
        y: 93
        text: "Hello World"
    }

    MouseArea {
        anchors.fill: parent;
        onClicked: {
            animator.duration = 1000;
            animator.to = 400;
            animator.easing.type = Easing.Linear;
            animator.start();
            }
    }

    NumberAnimation { id: animator; target: label; property: "x"; to: 100; easing.type: Easing.InBounce; duration: 5000; }

}