One way you could do it is to pass property values into your log, that way all you need to worry about is keeping your internationalized versions of the properties files up to date...
See here for more info
You seem to be pretty much there. All you should have to do is pass in the localized string when listing your log value e.g.:
As a word of advise, if you do go down this route, I would suggest that you override resourceBundle.getString, to pass back a default value if the locale cannot be found.