Deflate / Gzip Don't Work With Nginx Or Apache

Whatever i try to modify configuration there is no way i can get file delivered by apache or NGINX to be deflate/gzip compressed.

OS: Debian 7.7
Plesk version: 12.0.18 Update #33

I've tried to add these lines to Nginx (Vhost directives) but it change nothing :
# Gzip Settings
gzip on;
gzip_buffers 16 8k;
gzip_comp_level 4;
gzip_http_version 1.1;
gzip_min_length 1100;
gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/x-javascr$ application/xml application/xhtml+xml application/xml+rss;
gzip_vary on;
gzip_static on;
gzip_proxied any;
gzip_disable "MSIE [1-6].";

I also tried to disable Nginx and configure deflate in apache with following lines (Vhost directives then in a file in apache2/conf.d) but it is the same ...

<IfModule mod_deflate.c>
# Force deflate for mangled headers developer.yahoo.com/blogs/ydn/posts/2010/12/pushing-beyond-gzipping/
<IfModule mod_setenvif.c>
<IfModule mod_headers.c>
SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)s*,?s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding

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