Problem with navig.graphics And navig.showtitles

In my customization driver I have:

    <xsl:param name="use.id.as.filename">1</xsl:param>
    <xsl:param name="chunk.fast">1</xsl:param>
    <xsl:param name="use.id.as.filename">1</xsl:param>
    <xsl:param name="chunk.section.depth">1</xsl:param>
    <xsl:param name="admon.graphics">1</xsl:param>
    <xsl:param name="admon.textlabel">1</xsl:param>

    <xsl:param name="navig.graphics">1</xsl:param>
    <xsl:param name="navig.graphics.extension">.png</xsl:param>
    <xsl:param name="navig.showtitles">1</xsl:param>


But still only the images shows up: No "Next" or "Prev" texts. Shouldn't the 
above fix it?


Cheers,


			Frans