I've followed the steps you provided but I'm getting an error:
C:\projects\redbooth-outlook\Redbooth.Outlook.sln" (default target) (1) ->
"C:\projects\redbooth-outlook\Redbooth.Outlook.Test\Redbooth.Outlook.Test.csproj" (default target) (5) ->
"C:\projects\redbooth-outlook\Redbooth.Outlook\Redbooth.Outlook.csproj" (default target) (2:2) ->
C:\projects\redbooth-outlook\Redbooth.Outlook\Redbooth.Outlook.csproj(475,3): error MSB4019: The imported project "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\OfficeTools\Microsoft.VisualStudio.Tools.Office.targets" was not found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk.
Time Elapsed 00:00:04.16
Command exited with code 1
Is it a problem with the Office version (provided your example was working with v12.0? Or maybe I have to copy the target file to the Program files path?
Yes, that "recipe" was for VS 2013 (12.0) and you could adopt it
for VS 2015 (14.0). I guess there would be not only paths to
assemblies and target files, but different strong assembly versions
I copied the .targets files and now I'm getting this error:
C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\OfficeTools\Microsoft.VisualStudio.Tools.Office.targets(264,9): error MSB3482: An error occurred while signing: Invalid provider type specified.
I'm not really sure if it's related to the Clickonce certificate or it's still related to the previous VSTO dlls issues.
I've signed several Clickonce packages before in AppVeyor wihout any problem but in this case, the certificate had a .p12 extension instead of .pfx. I just changed the extension but I suspect (be looking a the error code above) that it has to do with some sort of server incompatibility.