Missing location when applying nested stylesheet with exception

[caillette]

When the level-title element isn't a correct identifier (like if it contains a space) there is such exception:

line=-1; column=-1 - java.lang.IllegalArgumentException: Name '' doesn't match [a-zA-Z0-9]+(?:[_\-][a-zA-Z0-9]+)*

The nested stylesheet looks like this:

<xslmeta:multipage>
  <xsl:template match="/" >
    <n:pages>
      <xsl:for-each select="/n:opus/n:level">
        <n:page>
          <n:page-identifier>
            <xsl:value-of select="n:level-title"/>
          </n:page-identifier>
          <n:page-path>/opus/level[<xsl:value-of select="position()"/>]</n:page-path>
        </n:page>
      </xsl:for-each>
    </n:pages>
  </xsl:template>
</xslmeta:multipage>

We should see the line number in the originating document. Problem: since this occurs in Opus files, the title belongs to some Novella. Probably the trick is to inject SourceLocation objects into the ContentHandler from the GenericRenderer.