I searched the form and couldn't find anything on this, if I missed it I am sorry. How do you get the sent mail folder to show up? Is this something you tell the server to make or round cube, and how do I do that?
find in config/main.inc.php
// automatically create the above listed default folders on login
$rcmail_config['create_default_folders'] = FALSE;
replace with
// automatically create the above listed default folders on login
$rcmail_config['create_default_folders'] = TRUE;