My name is Joan, I just discovered this great software and the first thing I tried to improve was the translation. Theres a website called transifex that has free services for the opensource communities.
They do support the .properties files and allow you to translate them online, thus avoiding mistakes and allowing you many other features, such as don't having to worry for the language encoding and that stuff.
I just created a project called ps3mediaserver to allow the testing for the users, I've been trying it with catalan and it works really great.
You can see the link here: https://www.transifex.net/projects/p/ps3mediaserver/
NOTE: I'll be glad to give all the control to the admins of the project if they are interested on this