uploading android applications files (.apk) with symfony2

[eluser]Unknown[/eluser]
Hello,
I am working on application that upload some kind of file from PC to the server. I am using Apache version 2.2.21. The kind of files are Android application package file (.apk). With when I am trying to upload .apk i obtain a compressed file (.zip):
I tried to fix the problem so i added :
'application/vnd.android.package-archive' => 'apk',in File.php , but it doesn't change anything.

What is missing or I have to do??