[horde] Getting user list when using IMP for authentication

[Aleksandar Milivojevic]

Jan Schneider wrote:
> Zitat von Aleksandar Milivojevic <alex at milivojevic.org>:
> 
> 
>>Quoting Ben Chavet <ben at horde.org>:
>>
>>
>>>>Hmmm...  But then I'd need to login twice (into Horde, and then into IMP)?
>>>
>>>No, just set 'hordauth' => true in imp's server config
>>
>>I was just looking into my servers.php file (looking if I could give
>>Jason some
>>advice with his SyncML problem), and noticed that option inthere ;-)
> 
> 
> You could also use a composite authentication driver.

I could, I guess.  But, is there a hook somewhere so that I can return 
list of users back to the Horde (for example, for editing permissions 
when sharing calendars in Kronolith)?