How to add my phtml in admin create order page?

Question

My code:

xml code:

<?xml version="1.0"?>
<layout version="0.1.0">
<adminhtml_sales_order_create_index>        
    <reference name="root">
        <block type="clientpo/adminhtml_sales_order_create_client" template="clientpo/client.phtml" name="client" after="form_account" />
 </reference>
</adminhtml_sales_order_create_index>
</layout>

Block code:

<?php

class Module_Clientpo_Block_Adminhtml_Sales_Order_Create_Client extends    Mage_Adminhtml_Block_Sales_Order_Create_Abstract
{
}
?>

Phtml code:

<?php echo "Hii";?>

But its not working where i am wrong?

Answer 1

xml code

<?xml version="1.0"?>
<layout version="0.1.0">
    <adminhtml_sales_order_create_index>
        <reference name="data">
            <block type="clientpo/adminhtml_sales_order_create_client" template="clientpo/client.phtml" name="client" after="form_account" />  
        </reference>
    </adminhtml_sales_order_create_index>
</layout>

add childHtml block in phtml file app\design\adminhtml\default\default\template\sales\order\create\data.phtml

<div id="order-form_account"><?php echo $this->getChildHtml('client') ?></div>