Blimey, you'd think writing an Eclipse plugin that supports localization would be 'out-of-the-box' by now on Eclipse 4.2.2. Seems not.
So you want to use properties that are translatable in your plugin.xml right? Easy peasy:
1) Create a plugin.properties file in your project and add some stuff:
views.category = my super category
2) add it to the build.properties entries:
3) add some super properties to your plugin.xml eg:
4) Launch the plugin, huh? What's this? I see a category '%views.category'. Boo.
5) Aaaaaah, I forgot the manifest entry!
6) I think I deserve a cup of tea now.