How to sign AppX from Desktop App Converter

I have been trying to sign the AppX generated by the D.A.C. in order to verify it works as expected, but it seems a self signed certificate is not enough.

I also tried to sign using my Comodo SHA256 certificate, but even if I make sure to use the same publisher name as the certificate in the manifest, I get

SignTool Error: An unexpected internal error has occurred.
Error information: "Error: SignerSign() failed." (-2147024885/0x8007000b)

I am starting to wonder if this does not mean I have to use Authenticode.

I would very much appreciate advice about what should be done by others who have succeeded.

I have been trying to sign the AppX generated by the D.A.C. in order to verify it works as expected, but it seems a self signed certificate is not enough.

We can use the -Sign flag when running the DAC to automatically sign your .appx package. Please see the details in Sign your converted desktop app

To deply the converted app, please notice the certificate should be installed on this machine, see my answer in Installation Failed after creating UWP with Desktop App Converter

I am starting to wonder if this does not mean I have to use Authenticode

Yes, the Authenticode programs include MakeCert, see here

------------Update(09/25/2016)-----------

Deploy your application using the add-appxpackage –register AppxManifest.xml cmdlet or by repackaging it using MakeAppx, see App packager (MakeAppx.exe)

Please locate to the Appx layout folder which contains AppxManifest.xml file, after updating this file to contain a reference to the VCLibs UWPDesktop framework package, open Powershell(as Administrator) and type:

add-appxpackage –register AppxManifest.xml

Note: if the package has been installed on this device, please uninstall it first, otherwise you will see the conflict exception