folders creation

[Gregorio Faraldo]

Hi All
I want to customize my customer folders for sent-mail and trash
EX.: 
sent-mail ----- > enviados
trash -------------> papelera
I change this parameters in the prefs.php file and i don't want to my 
customer can chage this again


// trash folder
// ITACOM trash por Papelera y true
$_prefs['trash_folder'] = array(
    'value' => 'Papelera',
    'locked' => true,
    'shared' => false,
    'type' => 'implicit'
);

// drafts folder
// ITACOM drafts por borrador y true
$_prefs['drafts_folder'] = array(
    'value' => 'Borrador',
    'locked' => false,
    'shared' => false,
    'type' => 'implicit'
);

// user folder path
// ITACOM se agrego INBOX.
$_prefs['folders'] = array(
    'value' => 'INBOX.',
    'locked' => true,
    'shared' => false,
    'type' => 'text',
    'desc' => _("Path to your mail folders:")
);


When the user log in for first time i want that this folders be created.
That work fine but now i upgrade to the last CVS version and when i try to 
save some mail in the Borrador folders for first time i get a error message 
that say
 
the folder "Borrador" was not created. This is what the server said: Invalid 
mailbox name
There was an error saving a draft.
What i can do ?
thaks in advance
Gregorio Faraldo