Puzzling solution with Jigsaw and Gradle (intentional pun)

After having watched Solving the Puzzle with Jigsaw and Gradle, I thought to give it a go.

Thus, I checked out the repository Hans Dockter apparently used for the presentation (https://github.com/gradle/gradle-modularity), and the latest Gradle (2.12).

Well, the example in the repository didn’t work out-of-the-box, and while I eventually could tweak the build.gradle files to compile and run, I am still not able to make Jigsaw modules, even though I’m running everything with a Jigsaw-enabled JDK 9 (b109). The *Jigsaw tasks which I can see Hans Dockter showcasing in the presentation do not seem to be available.

Do I need some Jigsaw-specific branch of gradle, or is the Jigsaw support simply not publicly available as of now? Or have I missed some simple configuration change?