W520 - No Stereo-Mix Functionality

When trying to record some audio playing on my pretty new W520 I learned for the first time that the stereo-mix functionality is not available on Thinkpads any more (and obviously has been removed for a few years already).
I wasn't aware of this crippling because it worked without problems on my old R51, and I would have never thought that a company would remove this useful functionality.

After experiencing the problem I did some research and found that it obviously already frustrated and angered a lot of users over the last few years.

I'm re-posting it here because I imagine there might be more users like me who also are not aware of this limitation.
And to add my frustration and anger to the chorus...