I do not get any settings under system properties related to the broadcast plugin. I have uninstalled the plugin by removing it from the plugins directory and downloaded a fresh copy and recopied it to the plugins directory. I expect to see plugin.broadcast.xxxx under system properties. This does not show up but it does show the plugin as being installed under the plugins tab. It also creates the plugin folder under the plugin directory.
Everything seems to work as expected with the plugin. I need to change the default behavior which restricts broadcast messages to your group only.
Openfire version 3.6.2 Broadcast plugin 1.7.0.