Tue, 5 Aug 2008 11:03:41 -0700 (PDT), /David Schwartz/:
> Tue, 05 Aug 2008 18:29:16 +0200, /Martin Honnen/:
>
>> If your variable contains a result tree fragment then you need to use 
>> xsl:copy-of instead of xsl:value-of e.g.
>>    <xsl:copy-of select="$bar"/>
> 
> That was it! Can you explain what the issue was a bit more fully?

<http://www.w3.org/TR/xslt#value-of>:

> The xsl:value-of element is instantiated to create a text node in 
> the result tree. The required select attribute is an expression; 
> this expression is evaluated and the resulting object is converted 
> to a string as if by a call to the string function. [...]
> 
> The xsl:copy-of element can be used to copy a node-set over to the 
> result tree without converting it to a string. See [11.3 Using 
> Values of Variables and Parameters with xsl:copy-of].

You could read about the 'string' function 
<http://www.w3.org/TR/xpath#function-string> and what is the 
string-value of root (and element) nodes 
<http://www.w3.org/TR/xpath#dt-string-value> (a bit down below). 
Such node is the one in your variable result-tree-fragment value 
<http://www.w3.org/TR/xslt#dt-result-tree-fragment>.

-- 
Stanimir