Portal Logout is now working in Internet Explorer 6.0 SP1 and higher. I tested it 
on a Portal 3.1.2 Systems and above. 

To make it work, uncomment the LOGOUT in the default.xml (and any other *.xml 
files in portal/roles

   <!--  <LOGOUT/>-->
     becomes
   <LOGOUT/>
and add the 'document.execCommand("ClearAuthenticationCache","false");'  line 
below in $WEBDIR/lawson/portal/logon.htm, so it looks like this

       if(document.location.hash=="#OUT")
       {
               var x=parent.httpRequest("/servlet/Profile",null,null,null,"LAWS
ON","LOGOUT")
               document.execCommand("ClearAuthenticationCache","false");
               if(x.status=="401")
               {
                       setCookie("AUTH","0")
                       parent.location.reload()
                       return
               }
        }