Security group on EC2 does not open proper port

Using the wordpress as an example, when I initiate the wordpress instance from Juju, it automatically assign two security group to the instance (juju-example & juju-example-1). One of the security group is coming from the bootstrap, and another one is from the wordpress own instance. Theoretically, one of the security group should have the port 80 open for others to access the apps. Same thing goes to the mysql instance security group.

Here is the command that I used:

1. juju bootstrap
2. juju deploy --repository=/home/shang/charms local:mysql mydb
3. juju deploy --repository=/home/shang/charms local:wordpress wordpress
4. juju add-relation mydb:db wordpress

From juju status, it all looks good:

2011-10-14 14:41:09,824 INFO Connecting to environment.
machines:
  0: {dns-name: ec2-67-202-56-62.compute-1.amazonaws.com, instance-id: i-2082be40}
  1: {dns-name: ec2-184-72-82-16.compute-1.amazonaws.com, instance-id: i-9e83bffe}
  2: {dns-name: ec2-107-22-25-117.compute-1.amazonaws.com, instance-id: i-867b44e6}
services:
  mydb:
    charm: local:oneiric/mysql-103
    relations: {db: wordpress}
    units:
      mydb/0:
        machine: 1
        public-address: ec2-184-72-82-16.compute-1.amazonaws.com
        relations:
          db: {state: up}
        state: started
  wordpress:
    charm: local:oneiric/wordpress-30
    relations: {db: mydb}
    units:
      wordpress/0:
        machine: 2
        public-address: ec2-107-22-25-117.compute-1.amazonaws.com
        relations:
          db: {state: up}
        state: started
2011-10-14 14:41:24,429 INFO 'status' command finished successfully