[horde] VHost

[kingping]

I tried horde 3.1.5 and 3.1.6 on CentOS 4 and FreeBSD 6.2-RELEASE with apache 1.3 and 2.2.6.
It works well when it's located somewhere like http://somesite.com/horde/ but Horde experiences problems when I try to configure it working with name-based virtual hosts this way:

====httpd.conf====
<VirtualHost *:80>
        ServerName horde.somesite.com
        DocumentRoot /usr/local/www/data/horde
</VirtualHost>

webroot config in config/registry.php:
    //'webroot' => _detect_webroot(),
    'webroot' => '',

Here's config/conf.php
http://pastebin.ca/875649

It logs in (/var/log/horde.log: Jan 28 15:52:44 HORDE [notice] [horde] Login success for kingping [192.168.2.83] to Horde [on line 90 of "/usr/local/www/data/horde/login.php"]) but redirects me back to login page. How can I solve it ?

And yepp, sorry for my language.