My problem is I need to explicitly reference the English properties file for the default non-localized message in the Exception.

The file name syntax is valid, see these examples: http://docs.oracle.com/javase/tutorial/i18n/resbundle/control.html

I think I have found a more elegant solution instead of symlinking which will probably make problems on Windows build hosts. The ResourceBundle fallback mechanism can help here. 

I'll commit the new proposal in the next commit :smiley: