Office 2016: Selfcert certificate not accepted - Where must it be saved to be recognized?

Hi,

I set my Office 2016 programs to only run VBA macros if the code has been signed by a certificate:

Next I created a self-signed certificate for my Office macros using Selfcert and assigned it to my VBA code:

But trying to run the certificate it doesn't seem to be accepted by, e.g., Excel 2016:

The Microsoft Support page "Digitally sign your macro project" contradicts itself by claiming to store the certificate (a) in the Trusted Root Certification folder or (b) in the Personal Certificates folder (both times in the "Current User" branch). So it's of no help.

Anyway: Both locations don't work.

Here are two screenshots depicting where the Selfcert certificate gets stored by default:

So where is the Selfcert certificate supposed to be stored for being accepted by Excel 2016 when running VBA macros?

This is an animated GIF demonstrating that VBA certificates are solely accepted in the "Personal Certificates" folder of the current user:

The video shows that you cannot store the certificate in any other Certificate Store folder.

Yet, even installing it to the only possible folder doesn't work.

Can someone reproduce the problem? Or can someone get a Selfcert certificate to run with above security settings?

PS: I'm running the German edition of Office on a German edition of Windows, so all screenshots are in German, I'm afraid. But I'm sure you can easily grasp the idea without translation.