[imp] INBOX label in left menu

[Oliver Schulze L.]

Hi,
I'm trying to change the INBOX label of the Inbox.
I'm using IMP4 with Horde3

So, I changed in /horde/imp/config/prefs.php
// user default mailbox
$_prefs['mailbox'] = array(
    'value' => 'Inboxtest',
    'locked' => false,
    'shared' => false,
    'type' => 'implicit');

But that does not change the INBOX label in the left menu. In the 
message pane,
the INBOX button does change to Inboxtest.

Is there any other place to edit so that the menu in left also display
the edited INBOX name?

Many thanks
Oliver

-- 
Oliver Schulze L.
<oliver at samera.com.py>