xsl:copy-of O.K. on RTF, but nothing on <EMPTY/> eleme

Greetings.

With this e-mail I'm looking to confirm if I am barking up the wrong
tree.

Can this be done?  Ought I to be trying a different approach?  
Maybe to modelling my XML (?), maybe to programming my XSLT (??)

Thank you for any help or clarification that can be offered.
William Reilly
wreilly@xxxxxxxxxxx
Boston, Massachusetts U.S.A.
===============

Below are 3 snippets:
- XML Main Data File
- XML Lookup File
- XSLT That Does document() Lookup

PROBLEM DESCRIPTION...

- I'm building up an xsl:variable (Result Tree Fragment (RTF)), 
	- by means of doing a simple 'document()' lookup, 
		- running an 'xsl:for-each' selection over in the lookup
file, 
			- and then an 'xsl:copy-of' to my result file of
the selected content I want from over there: 
				- (namely, what's between one set of the
<markup> tags. Pls. see below).
				
++ CASE # 1  (WORKING FINE)
	Here, what's found is a RTF: <markup>'s content can have either
Mixed Content, 
	or be simply #PCDATA.
	'xsl:copy-of' copies it all over, just fine.

	<markup>an <a
href="http://www.bank.com/CALIF/interest.html">Interest Maximizer
account</a>.</markup>


++ CASE # 2  (NOT WORKING)
	Here, what's found is apparently _not_ a RTF (?), but instead a
nodeset (??).
	This content is EMPTY ELEMENT ONLY.  (Not even any whitespace.)
	At any rate, xsl:copy-of gets no result back ("empty node list")

	(tried both Xalan and Saxon). 

	<markup><img src="images/california_header.gif"/></markup>


++ CASE # 2a (This WILL Work)
	Interestingly, here, if I introduce even a single space (!)
between 
	<markup> and <img>, it then works fine (becomes Mixed Content).

	<markup> <img src="images/california_header.gif"/></markup>


-=- A Few Words from the Recommendation...  -=-=-=-=-=-=-=-=-=
http://www.w3.org/TR/xslt#copy-of

11.3 Using Values of Variables and Parameters with xsl:copy-of

"...used to insert a result tree fragment"
"...(for) a node-set, all the nodes in the set are copied"

"The xsl:copy-of element can be used to insert a result tree fragment
into the 
result tree, without first converting it to a string as xsl:value-of
does... 
When the result of evaluating the expression is a result tree fragment,
the complete 
fragment is copied into the result tree. 
When the result is a node-set, all the nodes in the set are copied in
document 
order into the result tree; copying an element node copies the attribute
nodes, ... "
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

http://www.w3.org/TR/xslt#copying
7.5 Copying

"The xsl:copy element provides an easy way of copying the current node."
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-


=-=-  Conclusions, Thoughts, Wonderings... (?)  =-=-=-=-=-=-=-=-=
Hmmmm.  I don't truly understand everything about result tree fragments
and nodesets, 
but I am puzzled why the <img src="pic.gif"/> empty element can't get
successfully 
"xsl:copy-of'd" out of its position as the only node found inside a
container element
 'markup'. ? Odd, to me.  
Doesn't it say (above) in the Recommendation that "nodes in the set are
copied..." 
and "copying an element node copies the attribute nodes" ??

Aside: 
As for xsl:copy, I don't believe it fits the bill here, as I'm relying
on xsl:copy-of's "select" attribute to help me 1) pick the right
<markup> tag, then 2) copy it over right then and there.  xsl:copy seems
more suited to when you already have selected the node you want; I'm not
in that situation (to the best of my understanding (!?)).

As I say, I'd be interested to hear useful learnings on why this is not
working.  
In the meantime, I may just work on another approach to providing a
container for 
the <img> tags markup I need.

THANKS!
William Reilly
P.S. Also, for what it's worth, I just tried removing the document()
lookup from 
the equation by putting both XML files into one, and got identical
results.  
It's really an xsl:copy-of issue.



++++++++++++++++++++++++++
 3 FILE SNIPPETS
++++++++++++++++++++++++++
======================
XML Main Data File: ("lookup" is triggered on <main-msg> element)
----------------------
<td>some text <main-msg name="which-product"/> some more text</td>
<td><main-msg name="header-image"/></td>
----------------------


======================
XML Lookup File: (2 example 'msg's: which-product, and header-image)
----------------------
<msgs>
	<msg name="which-product">
		<segment name="CALIFORNIA">
			<markup>an <a
href="http://www.bank.com/CALIF/interest.html">Interest Maximizer
account</a>.</markup>
		</segment>
		<segment name="OREGON">
			<markup>a <a
href="http://www.bank.com/OREGON/money.html">Money Maximizer
account</a>, with no monthly fee.*</markup>
		</segment>
		<segment>
		...
		</segment>
	</msg>
	<msg name="header-image">
			<segment name="CALIFORNIA">
				<markup><img
src="images/california_header.gif"/></markup>
			</segment>
			<segment name="OREGON">
				<markup><img
src="images/oregon_header.gif"/></markup>
			</segment>
		<segment>
		...
		</segment>
	</msg>
	...
</msgs>
----------------------

======================
XSLT That Does document() Lookup:
----------------------
<xsl:param name="segment" select="CALIFORNIA"/>
...
<xsl:template match="main-msg">
	<xsl:variable name="msg-name" select="@name"/>
	<xsl:variable name="msg-fill-contents">
		<xsl:for-each
select="document($LookupFilename)//msgs/msg">
			
<!-- XSL:COPY-OF
		Works fine EXCEPT when <markup> contains EMPTY ELEMENT
ONLY content.
		e.g. <markup><img
src="images/california_header.gif"/></markup>
(Note: I tried both with and without final '/node()' step.)
	
==================================================================  -->
		<xsl:copy-of
select="segment/markup[ancestor::msg/@name=$msg-name  
					and  
	
ancestor::segment/@name=$segment]/node()"/>	
<!--
/==================================================================  -->

		</xsl:for-each>
	</xsl:variable>
		
		... (use the $msg-fill-contents variable)...

</xsl:template>
----------------------

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