Something like an attribute-set, but different

Hi all,

I've got a few situations where I'd like to set some attributes based  
on some top-level properties of my DocBook Book.  For example:
- If the <book>'s lang is "ja", use a set of Japanese fonts, rather  
than the defaults.
- If the confidentiality level of the document (my own tag) is  
"Confidential", print the chapter titles in black rather than blue.

How could I achieve this?  I've had some success using <fo:marker>  
and <fo:retrieve-marker> to set header and footer properties, but I'd  
like something more generic.  Has anyone attempted something like this?

Currently, users are having to provide some properties to the XSLT  
command-line (e.g. language) that could easily be inferred from the  
document itself.

Thansk,

Geraint North
Principal Engineer
Transitive