I am not sure about playing sound, but for vibration I am using following code, You can try that out if works for you.

void Sample::enableVibration()
{
#ifdef Q_WS_MAEMO_5
mDbusInterface = new QDBusInterface(MCE_SERVICE, MCE_REQUEST_PATH,
MCE_REQUEST_IF, QDBusConnection::systemBus(),
this);

mDbusInterface->call(MCE_ENABLE_VIBRATOR);

#endif
}

void Sample::vibrate(int aTimeout)
{
#ifdef Q_WS_MAEMO_5

mDbusInterface->call(MCE_ACTIVATE_VIBRATOR_PATTERN, "PatternIncomingCall");
QTimer::singleShot(aTimeout,this,SLOT(stopVibratio n()));
#endif
}

void Sample::stopVibration()
{
#ifdef Q_WS_MAEMO_5
mDbusInterface->call(MCE_DEACTIVATE_VIBRATOR_PATTERN, "PatternIncomingCall");
#endif
}