I am a Newbie and am having difficulties with an XSLT doing a lookup. I
need to lookup up an old file number based off of an attribute, look at
the lookup file and pull in the new number. I am using Oxygen Editor
version 22.1.

My XML file looks like this. I need to find the highlighted file in my
lookup and replace with the new file number.
<proc>
<title>FOLLOW-ON MAINTENANCE</title>
<step1 id="M20340-03.01.01">
<para> Install access cover. <xref wpid="M20236" pretext="(" posttext=")"/>
</para>
</step1>
<step1 id="M20340-03.01.02">
<para> Fill cooling system to proper fluid level. <xref wpid="M20333"
pretext="(" posttext=")"/>
</para>
</step1>

My Lookup file looks like this (only added a few rows)
<row><NewFile id="M20236">M20016-9-2350-372</Newfile></row>
<row><NewFile id="M20234">M20381-9-2350-372</Newfile></row>
<row><NewFile id="M20232">M20017-9-2350-372</Newfile></row>

   <xsl:template match="xref/@wpid[key('file-ref', ., doc('lookup.xml'))]">
      <xsl:attribute name="{name()}" select="key('file-ref', .,
doc('lookup.xml')"/>
   </xsl:template>

Of course the path and the lookup document is bested stored in a global
parameter or variable.