Qt + Ogre Mouse WheelEvent

I am trying to implement wheel event in Ogre Render window embedded in QWidget. I am modifying the example of QOgreWidget available at: http://github.com/gklingler/QOgreWidget.

It has a zoom function as:

Code:

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void QOgreWidgetDemo::onZoomIn() {
    mCamera->moveRelative(Ogre::Vector3(0, 0, -10.0));
}

---

I want to implement it using QWheelEvent. I have modified it to:

Code:

---

void QOgreWidgetDemo::onZoomIn(QWheelEvent *event) {
    qDebug() << "Wheel event"; 
    if(event->delta > 0){
    mCamera->moveRelative(Ogre::Vector3(0, 0, -10.0));
    }
}

---

This is not working. How should I proceed to implement wheel event in the Render Window?
Thanks in advance.