Deploying an XSLT filter in Tomcat 4.0

[Martin Coxall]

Does anybody know the current level of support for filters in Tomcat 4.0?

I have written a small filter to take the XML output from one of our 
servlets, and then dependent on a parameter in the ServletRequest, use Xalan 
to transform the XML to HTML, WML or VoxML as appropriate.

Unfortunately, I am completely unable to make Tomcat 4.0 chain the filter to 
the Servlet, so all I am getting is raw XML rather than HTML etc.

My current web.xml looks like (excluding prolog)

<web-app>
 
 <servlet>
  <servlet-name>EchoServlet</servlet-name>
  <servlet-class>uk.co.itouch.EchoServlet</servlet-class>
 </servlet>
 
 <filter>
  <filter-name>EchoFilter</filter-name>
  <filter-class>uk.co.itouch.EchoFilter</filter-class> 
 </filter> 

 <filter-mapping>
  <servlet-name>EchoServlet</servlet-name>
  <filter-name>EchoFilter</filter-name>
 </filter-mapping>

</web-app>

What am I doing wrong? How do I make Tomcat chain the filter to a servlet?
Do I have to invoke the servlet in a special way?

Thanks

Martin