[imp] Problem with default language and mbox file

[Mejdi Bouchlaghem]

Hi,

Here is my configuration:
------------------------------
Linux Redhat 9
Horde 2.2.3-1
IMP 3.2.1-1
Mysql-3.23.56-1.9
PHP 4.2.2-17
Apache httpd-2.0.40-21.1
Openssl 9.7
------------------------------

Does somebody know how to specify to IMP to auto-select "Francais" 
language entry for the login page.
I've specified these lines:
    $nls['defaults']['language'] = 'fr_FR';
    $nls['defaults']['charset'] = 'ISO-8859-1';
in horde/config/lang.php. 

and those in horde/imp/config/prefs.php
// user language
$_prefs['language'] = array(
    'value' => 'fr_FR',
    'locked' => false,
    'shared' => true,
    'type' => 'select',
    'desc' => _("Select your preferred language:")
);

But I still have an english login page.

I have also an another problem: 
All the messages that have been read by IMP are automaticly  
moved to the file $HOMEDIR/mbox file when exiting Horde/Imp.
I would like these messages being kept in /var/spool/mail/$USER and
not in $HOMEDIR/mbox .
If I remove the file  $HOMEDIR/mbox there's no more problem. But the 
fact is that some people use this file with other products.

Any ideas !!! Thank you !

Aprovecha la vida !!!
Hasta pronto 
mejdi