sorting and merging

hi everybody,
i'm new ot this list but maybe someone can can give me some help
to solve this problem i have.

(sorry if the explanation is going to be lengthy, but i had not found
a more concise way to express what i need to do. i hope this helps
clarity, thought.)

in my application (server side) i create an xml fragment from random 
user input, then i need to merge it into a "main" xml document after 
sorting it.

the structure of my main xml doc looks like:

("main.xml")

<ex>
   <qs>	
      <q type="S">
        <as>
	     <a>txt</a>
	     {...more <a>...}
        </as>
      </q>
	{...more <q>...}
   </qs>
</ex>
		
and the fragments i need to merge look like:

<temproot>
  <a new="3">txt</a>		
  <a new="1">txt</a>		
  <a new="2">txt</a>		
</temproot>
	
What i need to do is to first sort the <a>'s in the fragment based on the
"new" attribute,
then insert them in the main xml file *replacing* all the old <a>'s.
To make it simple suppose i wish to insert them always as childs of the
first <q> in the main xml doc. (i think i can parametrize this later).

Also i need, quite obviously, to remove the "new" attribute from the result,
since it's useful only as a sort device and not to the final xml.


Currently what i do is to create load the fragment in the processor and sort
the <a>'s with
a stylesheet like this one (boilerplate stuff killed):

<xsl:template match='/'>
	<xsl:apply-templates select="/temproot"/>
</xsl:template>
<xsl:template match='@* | node()'>
	<xsl:copy>
		<xsl:apply-templates select='@*[not(name()="new")] | node()'
>
			<xsl:sort select="@new" data-type="number"/>
		</xsl:apply-templates>
	</xsl:copy>
</xsl:template>

after this i have to resort to the loading the main xml and the sorted 
fragment in two DOMs and then "manually" strip all the childs <a>'s of 
the designated <q> and insert the new <a>'s in their place.


My idea is to use document() to load the main xml in the above stylesheet
and 
use it to perform also the part i currently do via the DOM, but so far i had
not been able to write a working stylesheet that does this.

Can someone please throw an hint at me ? Just an idea on how to tackle this
problem or some pieces of example stylesheet would be greatly appreciated.

Thanks in advance,
Ugo R. 

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