Problem with ajp proxy module

Hi,
No problem to make ajp module works but I have a problem with the
ajp_cache directive.It stores only one file in the cache and always
return this file.For example, if I call http://mon url/image.jpg, it
will returns this file even when I will call http://mon url/style.css.
Here is my config file :
#user nobody;worker_processes 1;
#error_log logs/error.log;#error_log logs/error.log notice;#error_log
logs/error.log info;
#pid logs/nginx.pid;

events { worker_connections 1024;}

http { include mime.types; default_type
application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local]
“$request” ’ # '$status $body_bytes_sent
“$http_referer” ’ # ‘“$http_user_agent”
“$http_x_forwarded_for”’;
#access_log logs/access.log main;
sendfile on; #tcp_nopush on;
#keepalive_timeout 0; keepalive_timeout 65;
#gzip on; upstream tomcat-preprod { server
pacaya.altima.fr:8012; keepalive 10; } ajp_cache_path
/var/www/cache levels=1:2 keys_zone=myzone:50m; server {
listen 80; server_name erp-preprod;
location ~ .(js|css|png|gif|jpg|ico)$ { ajp_pass tomcat-preprod;
ajp_cache_valid 60m; ajp_cache myzone; }
location /sx-preprod { ajp_keep_conn on; ajp_pass
tomcat-preprod; } location /sx { rewrite /sx /sx-preprod; }
location / { rewrite / /sx-preprod; } error_page 500
502 503 504 /50x.html; location = /50x.html { root
html; }
}
}
Any advice ?