why storm still use it's own zookeeper node not my zookeeper cluster?

[ch huang]

hi,maillist:
            i am a storm newbie ,when i start storm nimbus and suervisor ,i
check log and find the following info

2014-04-08 09:26:02 o.a.z.ZooKeeper [INFO] Client
environment:zookeeper.version=3.3.3-1073969, built on 02/23/2011 22:27 GMT
2014-04-08 09:26:02 o.a.z.s.ZooKeeperServer [INFO] Server
environment:zookeeper.version=3.3.3-1073969, built on 02/23/2011 22:27 GMT
but my zookeeper is  3.4.5 ,

# rpm -qa|grep zookeeper
zookeeper-server-3.4.5+23-1.cdh4.4.0.p0.24.el6.noarch
zookeeper-3.4.5+23-1.cdh4.4.0.p0.24.el6.noarch
my storm.yaml is

storm.zookeeper.servers:
    - 192.168.10.220
    - 192.168.10.221
    - 192.168.10.223
but why storm still use it's build-in zookeeper not my zookeeper cluster?