Kolab server 2.3.4 - motd.php problem

Hi,
	in a fresh kolab installation I add the following line in:

/kolab/etc/kolab/templates/webclient-config_motd.php.template

<br />
<table width="100%"><tr><td align="center"><img 
src="themes/graphics/RealT.png" alt="Powered by Horde" /></td></tr></table>

The I run /kolab/sbin/kolabconf

What happened is that the Horde image under login form disappear instead 
of changing as I suppose.

I reverted the template file to original, run kolabconf but the original 
horde image don't appear any more.

I also try to modify

/kolab/etc/kolab/templates/webclient-imp_motd.php.template

with:

<br />
<table width="100%"><tr><td align="center"><?php echo 
Horde::img('RealT.png', _("Powered by Horde"), '', 
$registry->getImageDir('horde')) ?></td></tr></table>

Nothing.

I reverted to original and I can't see original horde image.

Which is the correct procedure to change the image under login form?
How can I diagnose the problem?

Thanks.

-- 
ing. Andrea Gelpi
***************************************************
La Terra non la abbiamo ereditata dai nostri avi,
ma la abbiamo presa in prestito dai nostri bambini.
***************************************************
We do not inherit the Earth from our parents,
but borrow it from our children.
***************************************************