are you using QtGui or Cascades and which Qt version?
I think there are several ways to do that. Did you already look into the qnx platform plugin? The touch events are sent with QWindowSystemInterface::handleTouchEvent(w, m_touchDevice, pointList);
So you could hack it into the platformplugin somehow.
Another possibility would be to inject a bps screen touch event into the qt event loop. You might want to have a look at:
QQnxBpsEventFilter::nativeEventFilter(const QByteArray &eventType, void *message, long *result)
Qt on BlackBerry and QNX