Make your private post customizable, which can be setup in General Setting easily. You can even use specified tags to make each of private posts different. If you like this plugin please vote it, donations are very welcome and also ANY bug-reports and suggestions(you can post in wordpress forum).
If you like to translate this plugins, the .po files(translation file) in the “languages” directory under plugin directory.
after you’ve translated it please send it to wordpress(at)mengzhuo.org, and attach with po file name by what your language called in English.