How to center a fo:table on the titlepage

Hello all, 

I'm currently trying to center a table on my title page (in place of
<revhistory/>) 

I've put the following in my own titlepage.xsl 

----------------- 
<xsl:template match="d:revhistory" mode="titlepage.mode">

  <xsl:variable name="explicit.table.width">
    <xsl:call-template name="pi.dbfo_table-width"/>
  </xsl:variable>

  <xsl:variable name="table.width">
    <xsl:choose>
      <xsl:when test="$explicit.table.width != ''">
        <xsl:value-of select="$explicit.table.width"/>
      </xsl:when>
      <xsl:when test="$default.table.width = ''">
        <xsl:text>100%</xsl:text>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="$default.table.width"/>
      </xsl:otherwise>
    </xsl:choose>
  </xsl:variable>

 <!-- HERE'S MY TABLE -->
  <fo:table>
    <fo:table-column    column-width="30%"/>
    <fo:table-column    column-width="30%"/>
    .....
  </fo:table>

</xsl:template>
--------------------


And I've tried to put the following in my 'my.titlepage.xml'
  <t:titlepage t:element="book" t:wrapper="fo:block">
    <t:titlepage-content t:side="recto">
      <title ... />
      <revhistory padding-top='100pt' text-align="center" />
    </t:titlepage-content>


But my table is not centered it's printed on the left. But it's padding
from top for 100pt.
Is there anyone who can help please ?

Thanks you very much
Laurent