Writing English--Japanese documents using ruby / furigana in DocBook 5

[Róbert Kohányi <kohanyi.robert@gmail.com>]

I'm in the process of porting a Japanese language tutorial / textbook
of some sort to DocBook from HTML. I'd like to know if there's a way
to incorporate Japanese text with ruby / furigana above Japanese
words--into a document where the main body is written in English.

I've already set up a tool-chain for myself based on the best on-line
materials that I could possibly find[1][2] and I could produce HTML
and PDF files containing Japanese text properly--without ruby
obviously.

I'm doing something like this right now.

<para>English English <phrase xml:lang="ja">日本にほん</phrase>. English.</para>

I found a few posts on the mailing lists on this (or related) topics.
One of these posts[3] (by Normal Walsh) from June 2008 in essence said
that "support for ruby would be cool", but I couldn't find any
information on the topic aside from this.

Are there any progress on this matter? Where should one look for
tutorials, reference, anything on creating DocBook documents and
converting them to HTML and/or PDF with text containing ruby in it?
(Primarily HTML though, because I think PDF would be much harder--I'm
just learning DocBook and have only access to Apache FOP and the open
source tools of the like.)

Regards,
Kohányi Róbert

[1]: http://docbook.org/tdg51/en/html/
[2]: http://www.sagehill.net/docbookxsl/
[3]: http://markmail.org/thread/kl6ui4d7ut4nqlxm