jboss / tomcat session replication problem

- im using jboss 3.2.5 + with tomcat5.0 Apache+mod_jk(2)
- i have 2 separate servers with identical configuration of jboss
- i have ejb-application and web-application within <distributable/> tag
inside web.xml so when jboss starting we can see :

>20:01:59,944 INFO  [TomcatDeployer] deploy, ctxPath=/test,
warUrl=file:/F:/ejb/jboss-3.2.5/server/all/tmp/deploy/tmp62144webapp.war/
>20:02:00,074 INFO  [TomcatDeployer] ClusteredHTTPSessionService found


- on each instance of jboss ejb and web applications work correctly
- every thing is ok when im using sticky session in my apache+mod_jk2 ,
every request always goes to this same machine. Problem starts when each
request goes to diferent server :-( i see then the tomcat session is not
replicated

can anyone help me with this ??
regards
s0rs

ps: i read something that could be a problem with multicast
communication....
ps2: what is worth to mention is that the clustering tomcats 5.0 (not
integrated with jboss) works ok and sesion i replicated between 2
servers im using .