[xsl] sort by predefined order

[marentxml <mailing.lists@xxxxxxxxxxxx>]

hi

is there any way to sort elements by a predefined order? i'd like to  
come from

<source>
  <sortorder>46, 21, 39, 27, 17</sortorder>
  <elements>
    <element ID="17"/>
    <element ID="21"/>
    <element ID="27"/>
    <element ID="39"/>
    <element ID="46"/>
  </elements>
</source>

the most elegant way to

<target>
  <elements>
    <element ID="46"/>
    <element ID="21"/>
    <element ID="39"/>
    <element ID="27"/>
    <element ID="17"/>
  </elements>
</target>

thanks in advance for any help.

frank