[imp] Problem Folder Creation

[Vincent Couvreur]

My configuration :
    - Postfix
    - Cyrus 2.1.19-3
    - IMP H3-4.0.3


When i sent mail via imp, and it tried to create the sent-mail folder, imp repond 'permission denied'. It 's the same for the trash folder, spam folder.
But when i create a folder under the INBOX, no problem. 

I read on the mailling archive, i must configure servers.php, namespace to 'INBOX.' :

$servers['cyrus'] = array(
    'name' => 'Cyrus IMAP Server',
    'server' => 'localhost',
    'hordeauth' => false,
    'protocol' => 'imap/notls',
    'port' => 143,
    'folders' => '',
    'namespace' => 'INBOX.',

So can you help me please.