Re: [docbook] Arbitrarily start section numbering?

Yes, this can be done with a small customization:

<xsl:param name="start.numbering.at" select="0"/>

<xsl:template match="section" mode="label.markup">
 <xsl:choose>
   <xsl:when test="$start.numbering.at != 0 and not(ancestor::section)">
     <xsl:value-of select="$start.numbering.at"/>
   </xsl:when>
   <xsl:otherwise>
     <xsl:apply-imports/>
   </xsl:otherwise>
 </xsl:choose>
</xsl:template>