You have to tell the authors of the Audiobook Reader to publish the currently-playing audiobook title (and possibly author, if that is important) via ContextKit. This can be done on a high level using Qt Mobility:

http://doc.qt.nokia.com/qtmobility/publ-subs.html

The lower-level layer that's used (and can be used directly) is ContextKit:

http://harmattan-dev.nokia.com/docs/...providers.html

By the way, this is true for all other apps that want to display something in Billboard as well. Add support for ContextKit properties to the app, tell me how to get the app and the name of the ContextKit property, and I'll try to integrate support into Billboard.