[horde] User-ID mapping for Android/Outlook autodiscovery?

[Bjoern Voigt]

I am new with Horde 5.2. My Horde 5.2 installation uses a Courier
IMAP as authentication driver.

Manual configuration of Active Sync (Exchange) accounts on Outlook
2013 and Android 4.4 seams to work. I haven't tested the accounts
intensively.

But I can not get autodiscovery to run. I need some kind of userId
mapping. For instance userId "hans" (Courier IMAP user) has the
email address "hans.mayer at domain.com".

I tried different userId mapping hooks

config/hooks.local.php: authusername, preauthenticate and
activesync_get_autodiscover_username
imp/config/hooks.local.php: preauthenticate

To see, if the hooks are called I installed some debugging code
first, e.g. in imp/config/hooks.local.php

class IMP_Hooks {
    public function preauthenticate($userId, $credentials) {
        Horde::log("UserId input: ".$userId, 'ERR');
        $outuserid=$userId;
        return array(
          'credentials' => $credentials,
          'userId' => $outuserid
      );
    }
}

I found, that the hooks (authusername and preauthenticate) are
called within the normal Horde Webmail interface.

But in autodiscovery I see no debugging output in horde.log. I see
only the failing login from IMAP server.

Outlook 2013 sends "hans.mayer at domain.com" (Input
hans.mayer at domain.com) to IMAP. Android sends "hans.mayer". Of
course the authentication fails, because "hans" is the right username.

Any hints?

Greetings,
Björn