indexterm in legalnotice error

It looks like index terms in legalnotice are not
handled well by jadetex
backend. I'm using
openjade-1.3.1
jadetex-3.12
docbook-style-dsssl-1.78

following sample document:
---------------------------------------------------
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML
V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"[
<!ENTITY index SYSTEM "index.xml">]>
<book>
<title>test book</title>
<bookinfo>
<legalnotice>
<para>Legal Notice with an <indexterm>
<primary>Indexterm in
Legal Notice</primary> </indexterm> Index
Term</para>
</legalnotice>
</bookinfo>
<chapter>
<title>test chapter</title> <para>A paragraph an
<indexterm>
<primary>Indexterm in plain book</primary>
</indexterm> Index
Term</para>
</chapter>
&index;
</book>
---------------------------------------------------
Results, in PDF, in a two entries index. First one
refers to page "??",
second one to page "1". The index.xml file looks good
and index is OK
when compiling the document to HTML. I add that running
jadetex many
times has no effect.