DOCBOOK-APPS: Access to the root node in dsssl ?

I'm trying to have my dsssl transformation stylesheets guess the gi of
the root element (article, book, table, ...), so that I can output the
correct doctype line.

Unfortunately in the following clause the call to (gi) returns #f.
Anyone knows what the problem is ?

(root
    (make sequence
      (make document-type
	name: (gi (current-root))
	public-id: "-//Norman Walsh//DTD DocBk XML V3.1.3//EN"
	system-id: "/usr/lib/sgml/dtd/docbook-xml/docbookx.dtd")
      (process-children)))

I also tried various things, like (tree-root (current-node)) and such,
to no avail.  (children (current-root)) also returns an empty
node-list in this context, which seems suspicious to me.

-- 
Yann Dirson <>                 http://www.alcove.com/
Free-Software Engineer				      Ing幯ieur Logiciel-Libre
Free-Software time manager    	       Responsable du temps Informatique-Libre