How do I set a default value of an xsl dropdown list based on a session parameter?

Question

I have an XSL dropdown list that needs to be defaulted to a value based on a previously chosen value. Basically I have a work center that gets chosen and becomes a session param. When I open another page from the original I need it to show the dropdown with the default of that session param, which will be one of the items in a list of many. I am a novice with xsl and xslt. Code follows:

<select id="wcfound"  name="wcfound" style="height:40;width:126;"  tabindex="40" >
    <option value="ND">SelectWorkCenter</option>
        <xsl:for-each select="Row">
    <option>
        <xsl:value-of select="work_center"/> - <xsl:value-of select="description"/>
    </option>
        </xsl:for-each>
</select>

It gets processed and displayed through a servlet:

<SERVLET NAME="Illuminator">
<PARAM NAME="QueryTemplate"VALUE="APEX/Queries/EX/workCenterSelectionQuery"/>
<PARAM NAME="StyleSheet" VALUE="/XMII/CM/APEX/xsl/page/qualitywcfound.xsl"/>
<PARAM NAME="Param.1" VALUE="{plantId}"/>
<PARAM NAME="Content-Type" VALUE="text/xml"/>
</SERVLET>