The active and lock notifications are only sent when MCE sends the tklock_mode_ind signal and that only happens on my n810 when the hardware lock button is pressed. The lock signal is also sent by MCE when you long press the on-screen lock button. It isn't however sent when the power button unlocks the screen but I'm working on manually displaying the unlock notification.

This mimics the behavior of systemui on my tablet and I will need more detailed information from both of you if it is doing something different.