I am using Docbook XSL 1.72

Let's say I provide this when processing chunk.xsl:

<xsl:param name="html.stylesheet" select="'style.css'"/>

All my chunked html files now have:

<link rel="stylesheet" href="style.css" type="text/css" />

Now, I put:

<?dbhtml dir="subdir" ?>

into one of my chunked sections.  The corresponding chunk goes into subdir, 
but subdir/foo.html has an identical link, also with href="style.css", but 
it should really be ../style.css!

What are my options to do this right?  Unless there's a way to get this 
right, I'll have to churn the results through a custom XSL hack that adjusts 
the relative stylesheet link :-(

I'm also looking at what happens to all the admonition graphics, I suspect 
the same problem affects them, too :-((