DOCBOOK-APPS: Sorting and non-en_US indexes

[David Cramer <dcramer at broadjump dot com>]

We're going to have some DocBook documents localized in a number of
languages and generate html, html help, and pdfs using an xsl-based
toolchain. Running some basic tests with a Japanese document, things
generally work ok for all formats, but I haven't tested an
autoidx.xsl-generated index yet. Some posts make me think that sorting
of non-English indexes might be a problem:

http://lists.oasis-open.org/archives/docbook-apps/200208/msg00200.html
http://lists.oasis-open.org/archives/docbook-apps/200111/msg00339.html

Poking my head in autoidx.xsl (which, unsurpisingly, mystifies me), I
notice the xsl:sorts don't have lang attributes. On the other hand, the
DocBook community is pretty international, so I should think that if
there were serious problems, there'd be more posts about it. Could
somebody give me an indication of the status of generating indexes using
the DocBook xsls and various languages?

A related question regards xsl processors and sorting. I checked Saxon's
mailing list, but couldn't tell whether I could expect it to sort
correctly out-of-the-box or if we'd have to do a little work:
http://sourceforge.net/mailarchive/message.php?msg_id=77605
http://sourceforge.net/mailarchive/message.php?msg_id=1048531

Some recent threads give an indication of what tools to consider
<http://lists.oasis-open.org/htdig/bin/htsearch?config=lists_oasis-open_
org&restrict=%2Fdocbook-apps%2F&method=and&sort=score&words=japanese>
and mention xsltproc, but I didn't notice any discussion about sorting
or indexing wrt the xsl processor. 

Current tools:
* Docbook xsls, 1.50.0, 1.53.0
* Saxon 6.5
* XEP 2.7

Thanks,
David