DOCBOOK-APPS: index links for chunked HTML broken

Is the generated book index supposed to find HTML chunks when you create them
in different directories from the root (using either the dbhtml PI
or the use.id.as.filename param)?


I have a document like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "docbookx.dtd" [
<!ENTITY dummy SYSTEM "dummy.xml">
<!ENTITY about  SYSTEM "about.xml">
<!ENTITY journal SYSTEM "journal/journal.xml">
]>
<book>
&dummy;
&about;
&journal;
<index/>
</book>

No matter what I try, the index links include only the filename, not
the path information, as in <a href="journal.html#content"

Am I missing something, or do I need to customize the stylesheets?

I'm using saxon 6.5.3 and docbookxsl 1.67.0.