[imp] from_addr hook

[Tim Gorter]

Trying to get the hook system to work in head.

following on from included instructions, it does not seem to work, so if 
someone can point me in the right direction, much appreciated.

talking 
if (!function_exists('_prefs_hook_signature')) {
in hooks.php

to activate it
quote
For preferences, set 'hook' => true in that preferences attributes

I go to imp/config/prefs.php and add
// user preferred email address for From: line
$_prefs['from_addr'] = array(
    'value' => '',
    'locked' => false,
    'shared' => true,
    'type' => 'implicit',
    'hook' => true
);

but nothing happens, I made sure there was no entry in the database for the 
user. To tell you the truth I checked imp/lib/Identities/imp.php and cannot see 
any check for hooks there either.

help appreciated,
tim.