problem with missing "ALT"-tags

[Chris J. Mutter]

hello, 

it seems that the image-ALT attribute is not generated as explained
in: fdp-primer/sgml-markup-docbook.html: 

 ---cut---
<mediaobject>
  <imageobject>
    <imagedata fileref="fig1">
  </imageobject> 

  <textobject>
    <literallayout class="monospaced">+---------------+
|       A       |
+---------------+</literallayout>
  </textobject> 

  <textobject>
    <phrase>A picture</phrase>
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
  </textobject>
</mediaobject>
 ---cut--- 

when i generate a html file the ALT tag is missing. is this feature
working at all? 

i.e.: 
http://www.freebsd.org/doc/en_US.ISO8859-1/articles/vm-design/vm-objects.htm 
l or even the installation part of the handbook which contains
images does not contain ALT tags... 

please have a look, 

thanks,
cjm