Superscript text

Superscript doesn't seem to be working for

<fo:block font-size="8pt">
        square
        <fo:inline baseline-shift="super" font-size="6pt">2</fo:inline>
</fo:block>

Is anything wrong with this?

Regards,
Satish

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list