This code works fine, using jboss-seam-2.0.2.SP1, IE6

Not sure if it will help.... but can be tried.

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
                xmlns:s="http://jboss.com/products/seam/taglib"
                xmlns:ui="http://java.sun.com/jsf/facelets"
                xmlns:f="http://java.sun.com/jsf/core"
                xmlns:h="http://java.sun.com/jsf/html"
                xmlns:a="http://richfaces.org/a4j"
                xmlns:rich="http://richfaces.org/rich
"

                template="layout/template.xhtml">
                      
<ui:define name="body">
<h:messages globalOnly="true" styleClass="message" errorClass="errors" infoClass="info" id="globalMessages"/>

<h:form>
.......
<div class="actionButtons">
<h:commandLink id="update" value="Update Data"

action="#{quantDataHome.update}"
rendered="#{quantDataHome.managed}">

<rich:componentControl for="panel" attachTo="update" operation="show" event="onclick"/>

</h:commandLink>
</div>
</h:form>
<f:subview xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich
">


<rich:modalPanel id="panel" width="400" height="120">
<f:facet name="header">
  <h:panelGroup>

   <h:outputText value="Request In progress... Please wait..."></h:outputText>
  </h:panelGroup>
</f:facet>
<h:form>

<f:facet name="controls">
  <h:panelGroup>
   <h:graphicImage value="/images/modal/close.png" styleClass="hidelink" id="hidelink"/>
   <rich:componentControl for="panel" attachTo="hidelink" operation="hide" event="onclick"/>
  </h:panelGroup>
</f:facet>

<h:outputText styleClass="info" value="Your request is in progress, please wait....."></h:outputText>
</rich:modalPanel>       
</f:subview>