Session share

Hi, i have a HA enviroment with two server in testing and i can't to make it work the session share with memcache.

My memcache.ini have this:

; Use memcache as a session handler
session.save_handler=memcache

; Defines a comma separated of server urls to use for session storage
session.save_path="tcp://memcache_server:11211?persistent=1&weight=1&timeout=1&retry_interval=15"

Everything works, but the session seems independent on each server.

Does anybody know?

Thanks in advance.