default xsl files?

I'm using docbook, and I have read up about PUBLIC identifiers, and
the /etc/xml/catalog file pointing to local DTDs.

I want to have the same basic functionality with xsl
files...basically, the docbook xsl files are in or around the same
path: /usr/share/xml/.../docbook/stylesheets/

however this path may change...depending on the box.

Any idea how I can dynamically (at the OS level) provide the XSL file
to use from within my script?
Also, there may be a case where I need to override a docbook xsl file
but still use the other un-modified versions:

ie:

/my_files/foo.xsl (customized version)
/distro_files/foo.xsl (original version)
/distro_files/bar.xsl (original version)

So for example, if there is a "/my_files/foo.xsl" use that one,
otherwise use the "/distro_files/" versions.

I realize this is may not specifically relate to XSLT (perhaps) but I
do see how it is done with DTDs and XML, just need a similar mechanism
for maintaining my stylesheets.



-- 
Anthony Ettinger
Ph: 408-656-2473
var (bonita, farley) = new Dog;
farley.barks("very loud");
bonita.barks("at strangers");

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