Hi there. My touchpad does make a sound when placed properly in the touchstone. I did notice though that the touchpad charging/sound only occurs when in a) landscape mode the center button (not sure what to call the push button) is oriented to the right side of the screen. If that button is on the left side of the screen it does not charge in landscape.
For portrait mode, b) mine only charges when the center button is oriented at the bottom of the screen (and the video chat camera lense it at the top).
So basically it only charges in 2 of 4 possible ways to place it on the touchstone (where you can see the screen of course). I believe the directions that came with the touchstone match what I've tried to describe.
Note: Mine charges fine in the touchstone with the case on and the case cover folded back under the touchpad. So it charges through two layers of the case just fine. It is more stable in the landscape position though with the case on.