Is it possible to prevent session lost when restarting memcache?

Testing our new EC2 setup I noticed that when we restart memcache, the users lost their session and have to login again to the website?

This is our config:

$conf = array_merge($conf,array(
    'memcache_key_prefix' => 'pre_example.org', 
    'cache_inc' => './sites/all/modules/memcache/memcache.inc',
    'session_inc' => './sites/all/modules/memcache/memcache-session.inc',
    'memcache_servers' => array(
        'localhost:11211' => 'default',
        'localhost:11212' => 'page',
        'localhost:11213' => 'filter',
        'ec2-base-internal.example.org:11211' => 'default',
        'ec2-base-internal.example.org:11212' => 'page',
        'ec2-base-internal.example.org:11213' => 'filter',
        'ec2-base-internal.example.org:11214' => 'session',
    ),
    'memcache_bins' => array(
        'session'      => 'session',
        'cache'        => 'default',
        'cache_menu'   => 'menu',
        'cache_page'   => 'page',
        'cache_filter' => 'filter',
        'cache_block'  => 'default',
        'cache_content'=> 'default',
    ),
)
);

Thanks in advance, Simon.