How do I create custom fields like mobile number in customer registration form without modifying magento core files? I tried but the mobile number is not saved in the DB
I override the Mage_Customer_Model_Entity_Setup class with Myown_Mage_Customer_Model_Entity_Setup by creating Model/Entity/Setup.php in my modules folder and added the following code to the array in getDefaultEntities
'mobilenumber' => array(
                        'label'        => 'Mobile Number',
                        'visible'    => true,
                        'required'    => true,
                    ),
also my config file contains following code
<models>
        <customer_entity>
            <rewrite>
                  <customer>Myown_Mage_Customer_Model_Entity_Setup</customer>
            </rewrite>
        </customer_entity>
    </models>
Also i have this field in template/customer/form/register.phtml
<input type="text" name="mobilenumber" id="mobilenumber" value="<?php echo $this->htmlEscape($this->getFormData()->getMobilenumber()) ?>" title="<?php echo $this->__('Mobile Number') ?>" class="required-entry input-text" />  
Is there any thing I miss in this configuration? I want to save the mobile number in the DB and retrieve it afterward.