Magento管理菜单开发

我正在学习Magento Admin菜单的开发。我正在尝试在Magento管理面板中开发一个简单的菜单。我的代码如下

文件位置：app/etc/modules/Alanstordotcom_Helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<config>
    <modules>
        <Alanstormdotcom_Helloworld>
            <active>true</active>
            <codePool>local</codePool>
        </Alanstormdotcom_Helloworld>
    </modules>
</config>

文件位置：app/code/local/Pulsestorm/Adminhello/etc/adminhtml.xml

<?xml version="1.0"?>
<config>
    <menu>
        <pulsestorm translate="title" module="pulsestorm_adminhello">
            <title>Pulse Storm</title>
            <sort_order>1</sort_order>
            <children>
                <example>
                    <title>Example</title>
                    <sort_order>1</sort_order>
                    <action>adminhtml/adminhello/index</action>
                </example>
            </children>
        </pulsestorm>
    </menu>
</config> 

文件位置：app/code/local/Pulsestorm/Adminhello/etc/config.xml

<?xml version="1.0"?>
<config>
    <config>    
        <modules>
            <Alanstormdotcom_Helloworld>
                <version>0.1.0</version>
            </Alanstormdotcom_Helloworld>
        </modules>
    </config> 
    <global>
        <helpers>
            <pulsestorm_adminhello>
                <class>Pulsestorm_Adminhello_Helper</class>
            </pulsestorm_adminhello>
        </helpers>
    </global>
</config>

文件位置：app/code/local/Pulsestorm/Adminhello/Helper/Data.php

<?php
class Pulsestorm_Adminhello_Helper_Data extends Mage_Core_Helper_Abstract
{
}

但我在管理面板上看不到任何菜单。这里有什么问题？？感谢