<subtitle>s in <table>s

Has the possibility of having <subtitle>s on <table>s (and maybe
<figure>s) ever come up?

Currently <subtitle>s occur on a lot of elements, including <section>s,
<screenshot>s, <task>s, etc.--but not on <table>s (or <figure>s).  We have
an application where we would like to have subtitles on tables, and while I
can make a local modification to the DB5 schema and our .xsl files, this
may be something that would be more generally useful.

Or maybe I should be using the <caption> element... At the moment, it's
not clear to me how--or whether--<title> and <caption> are intended to work
together, particularly since in the XML, the <title> precedes the <tgroup>
and the <caption> follow it.  Post-processing can change this order, I
guess, but it at least makes it look as if they're not intended to work
together.

   Mike Maxwell