[xsl] XPath question concerning distinct-values()

[Thorsten <xsl-list@xxxxxxxxxxxxx>]

Hello,

I have a terrible SAP export that looks (simplified) like this:

<pricelist>
   <item>
      <title>Lorem Ipsum Dolor Sit Amet</title>
      <order-number>XY7020280901</order-number>
      <price>12.00</price>
      <unit>50</unit>
   </item>
   <item>
      <title>Some Title</title>
      <order-number>XY9010200901</order-number>
      <price>19.00</price>
      <unit>50</unit>
   </item>
   <item>
      <title>The Same Item With A Different Title</title>
      <order-number>XY9010200901</order-number>
      <price>19.00</price>
      <unit>50</unit>
   </item>
   <item>
      <title>Lorem Ipsum Dolor</title>
      <order-number>XY7010220201</order-number>
      <price>18.00</price>
      <unit>50</unit>
   </item>
</pricelist>

I want to select each <item> with different <order-number>. Simply
distinct-values(/pricelist/item) doesn't work because the <title> of item[2] and
item[3] are different.

My output should look like this:
XY7020280901  12.00
XY9010200901  19.00
XY7010220201  18.00

I'm using XSLT2.0 with Saxon 9.2 PE.

Any ideas?

Many thanks in advance.

Kind regards
Thorsten