Sorting unique and sub-total problem

I am struggling with what is turning out to be a rather nasty problem using
FOP  0.20.5 .  I have a set of unordered nodes along the lines of :...

      <ITEM item_id='1'>  <CARD number='123456789' \>  <AMOUNT amt='100'\>
</ITEM>
      <ITEM item_id='2'>  <CARD number='987654321' \>  <AMOUNT amt='30'\>
</ITEM>
      <ITEM item_id='3'>  <CARD number='123456789' \>  <AMOUNT amt='200'\>
</ITEM>
      <ITEM item_id='4'>  <CARD number='123456789' \>  <AMOUNT amt='50'\>
</ITEM>


The <ITEM> nodes can be in any order.  What I would like to get at the end
is the following out put.

      Card: 123456789  Total:350
      Card: 987654321  Total:  30

At the moment I can't even sort unique! I have tried to sort the nodes and
then compare the current node to the following sibling, using...

<xsl:for-each select=".//ITEM" >
<xsl:sort select="CARD/@number" order="ascending" />
      <xsl:if test="./CARD/@number[ not
(.=following-sibling::ITEM/CARD/@number) ]">
            ....print number etc. etc....

But what I have found is that the following sibling is as it would be if
the nodes have not been ordered.  I have proven this to myself using
something along the lines of...

<xsl:for-each select=".//ITEM" >
<xsl:sort select="CARD/@number" order="ascending" />
      <fo:block>
            CUR NUMBER: <xsl:value-of select=".//CARD/@number"/>
            NXT NUMBER: <xsl:value-of select="following-sibling::
*/CARD/@number"/>
            CUR ID IS: <xsl:value-of select="./@item_id"/>
            NXT ID IS: <xsl:value-of select="following-sibling::
*/@item_id"/>
      </fo:block>
</xsl:for-each>

I fear that the only way to deal with this is to use XSLT to preorder the
nodes and then use a 2nd script using the same approach as described.
Alternatively I could go right back to the process that originally created
the XML file and order / sub total from there... something I really want to
avoid if at all possible.

Is there another approach I can take ?  Am I expecting too much from XSLT
with all this... ?

Thanks for any help in advance...

Roger.


***************************************
Roger Wyatt
Principal Consultant
Nomad Software Ltd.
***************************************
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