Can you please tell where you read that?
I read this specification in RichFaces Developer Guide, at section 2.3.
There is a extraction of document
2.3. Supported Servers
â€¢ Apache Tomcat 5.5 - 6.0
â€¢ BEA WebLogic 9.1 - 10.0
â€¢ Resin 3.1
â€¢ Jetty 6.1.x
â€¢ Sun Application Server 9 (J2EE 1.5)
â€¢ Glassfish (J2EE 5)
â€¢ JBoss 4.2.x - 5
Thank you for pointing on that! I've created a bug: https://jira.jboss.org/jira/browse/RF-4531 to get the information updated.
Note that Websphere comes with JSF 1.1 out of the box and this JSF version in unsupported by 3.2.x RF versions. Here: http://docs.jboss.org/seam/latest/reference/en-US/html/websphere.html you can find som useful information.