I'm using Audirvana to listen my music (Audirvana is a "bit perfect" application which provides a much more better sound than ITunes). 
I'm searching a way to have a "file browser" for this application, on the same way than Itunes.

Does anyone know how to proceed ?

Thank you for your help 

Depending on whether Audirvana can be used to directly play an audio file and how the audio files are organized, you could use Remote Buddy's file browser for this. I suggest:

1) Use "Files" in Remote Buddy's menu (top level) 
2) Browse to the file you want to listen to 
3) Select it 
4) Choose "Audirvana" as application.

You can also add a file browser for a particular part of your drive anywhere in Remote Buddy's menu simply by dragging and dropping it from the Finder to the respective place in Prefs > Menu.

Cheers, 
Felix