DOCBOOK: including elements with xpointers xincludes

I would like to include a specific element from one file in another 
file. For example. I have a glossary in which every entry has a shot 
definition, and perhaps a longer definition.  I want to pull the content 
of the short <glossdef/> into one of the chapters in my book. I've been 
attempting things such as:

<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"  
href="../glossary.xml#xpointer(id('urðrshort')/*)"/>

When I run xsltproc on it to generate the target.db, I get "XInclude: 
failed build URL". If I simply use ...#xpointer(id(/glossary/*) I get 
all the entries in the glossary pulled in where the xinclude is located. 
 Should I be able to do what I'm attempting?  What is the syntax for this?

TIA

-- 
STH
Hann er vitrastr ásanna ok fegrst talaðr 
ok líknsamastr, en sú náttúra fylgir 
honum, at enginn má haldast dómr hans.