Let me recommend Purple Technology's XPath Explorer (http://sourceforge.net/projects/xpe/)

I copied your XML to a file, opened it in XPath Explorer, and determined
this XPath in a few seconds.:
  //record/field/../field[1]

or in expanded form:
  /descendant-or-self::node()/child::record/child::field/parent::node()/child::field[1.0]

This may not be the most efficient XPath, but it is a good starting point.

<xsl:if test="not(@id=preceding-sibling::field[1]/@id)">
>
> <!-- perhaps use a key here? -->
>        <xsl:value-of
>           select="$/document/configure/server/resultfield[@id=$id]"/>
>        <xsl:text>: </xsl:text>
>     </xsl:if>

<xsl:if test="not(@id=preceding-sibling::field[1]/@id)">
>
> <!-- perhaps use a key here? -->

        <xsl:value-of
         select="/document/configure/server/resultfield[@id=$id]"/>

>        <xsl:text>: </xsl:text>
>     </xsl:if>