Apache 1.3 + JBoss Load Balance with sticky session

Hi:

I have set up mod_jk load balance.
1. in worker.properties:
all the local_worker set to 0
include local_worker_only=0
sticky_session=1
And it point to 3 workers(JBoss instances)
node name is: node1, node2, node3

2. in Jboss setting, jboss-service.xml, for each node,
I defined <Engine jvmroute=node1 name=standalone
defaulthost=localhost debug=0>

When I connect the site , I found same session requests hit different
nodes and the error happened. Any missed steps that I should do to
really enable sticky session.

Thanks in advance.

jiliu