[docbook] Indexterm in glossterm causes validationexception when using glossseealso

Hi!

I am using xsltproc (libxml 20902, libxslt 10128) and I have the following glossary for testing purposes. Note the <glossterm>-tags have <indexterm>-tags each and there is also one <glossseealso>-tag. 

<?xml version="1.0" encoding="iso-8859-1"?><!DOCTYPE glossary PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"        "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"><glossary id="glossar">    <title>Glossar</title>    <!-- ................... E ................... -->    <glossdiv id="gloss_E">        <title>E</title>        <glossentry id="gloss_e-file">            <glossterm id="glossterm_e-file">                <indexterm>                    <primary>E-File</primary>                </indexterm>                <emphasis role="bold">E-File</emphasis>            </glossterm>            <glossdef>                <para>                    Glossary_Text                </para>                <glossseealso otherterm="gloss_test">EinTest</glossseealso>            </glossdef>        </glossentry>                      <glossentry id="gloss_test">            <glossterm id="gt_gloss_test">                <indexterm>                    <primary>EinTest</primary>                </indexterm>                <emphasis role="bold">EinTest</emphasis>            </glossterm>            <glossdef>                <para>                    Glossary_Text                </para>            </glossdef>        </glossentry>            </glossdiv></glossary>

When I try to generate a pdf file using apache fop (version 1.1), I will get a ValidationException:

org.apache.fop.fo.ValidationException: Property ID "idp8750595088" (found on "fo:wrapper") previously used; ID values must be unique within a document!

It is because of the <glossseealso>-tag. When resolved, a fo:wrapper-element is created with the same ID as the gloss_test. 

Now, if I move the <indexterm>-tag out of the <glossterm>-tag, it works just fine. 

I wonder if this is a bug or just a wrong use of the <indexterm>-tag. According to the DTD the <indexterm>-tag is an allowed child of <glossterm>.

Thanks in advance!

Best regards,

Dark.Rider85