[horde] Horde DocumentRoot

[Ollie Maitland]

Horde -

I have a pretty simple problem when trying to install horde on a second 
server but I can't see how to configure horde to use the document root 
as supposed to /horde

In apache I have :

<VirtualHost *:80>
ServerName email.domain.com
ServerAlias www.email.domain.com
ServerAdmin info at domain.com
DocumentRoot /usr/local/apache2/htdocs/horde
</VirtualHost>

And then when I go to email.domain.com I get forwarded (from index.php) 
to /horde/login.php

How do I change horde to use /login.php - or is this a problem with my 
httpd.conf (also the email.domain.com is an A record from another server)

Many thanks,

- Ollie Maitland