Option jarPath does not work

The option "jarPath" does not seem to work. If I use it to sign a jar that is not the primary output of my build, then it does not seem to work. Example: Use the assembly plugin to create a jar-with-dependencies jar. Try to sign this jar with: jar:sign -DjarPath=path/to/generated-assembly.jar. The output will show that the normal output jar of your project will be signed.