DOCBOOK-APPS: Refentries in book TOC

["Bradford, Denis" <denisb at rational dot com>]

Here's a problem generating HTML using docbook.xsl 1.49 (1.48 too): An
<indexterm> in a <refname> seems to foul up generation of links in the book
TOC. Is this a bug?

************* diff.xml fragment ***************
<refentry id="diff_refentry_25973">
<?dbhtml filename="diff.html"?>
<refnamediv>
  <refname>
    <indexterm id="indexterm_14213523">
       <primary>versions</primary>
       <secondary>merging</secondary>
    </indexterm>Diff
  </refname>
   ...

************* HTML generated in book TOC ***************
<dt>
    <a href="diff.html">
       <a class="indexterm" name="indexterm_14213523"></a>Diff 
    </a> - Compares or merges text files
</dt>
****************************

The <a> here identifies the link target, but the text, Diff, is not
underlined and not active. If I move the indexterm somewhere else (like,
before the refnamediv), TOC links work. 

Clearly, fixing the XML is one workaround, but a stylesheet fix would be
better. Anybody know what template to customize? - it's not real clear to
me.

Thanks,
Denis