How to select different audio language?

Hey!

I have one problem with nitoTV:

I have some movie files with more than one audio language. I tried to hold the menu button to select a language while playing a movie, but this only makes the menu screen appear. Is it possible to switch between German and English audio language?

I also tried setting the language in the Apple TV Settings > Audio & Video but this did not change anything…

Thanks in advance for any help!