[SOLVED] Magento - Extra Address Fields (during registration)

At customer registration:

By default, Magento uses the supplied customer name to auto-populate the default shipping / billing information. We are a B2B, and need to gather that information separately at the time of registration. Additionally, we need to get the address fax number.

These are not custom attributes (already made a bunch of those, and have integrated them into a greatly expanded registration form), but the standard first name, last name and fax fields associated with a customer address.

I've attempted this:

        <span class="msg">Default shipping and billing information.</span>
        <ul class="form-list">
            <li class="fields">
                <div class="field billing_name">
                    <label for="billing_firstname" class="required"><em>*</em><?php echo $this->__('First Name') ?></label>
                    <div class="input-box">
                        <input type="text" name="billing_firstname" id="billing_firstname" value="<?php echo $this->htmlEscape($this->getFormData()->getFirstName()) ?>" title="<?php echo $this->__('First Name') ?>" class="input-text required-entry" />
                    </div>
                </div>
                <div class="field billing_name">
                    <label for="billing_lastname" class=""><em>*</em><?php echo $this->__('Last Name') ?></label>
                    <div class="input-box">
                        <input type="text" name="billing_lastname" id="billing_lastname" value="<?php echo $this->htmlEscape($this->getFormData()->getLastName()) ?>" title="<?php echo $this->__('Last Name') ?>" class="input-text required-entry" />
                    </div>
                </div>
            </li>

but I'm not clear what the input name should be. Whatever the case, the account names are used instead.

Looking for a little information on maybe the "name" of the form fields required, and some method of disabling the auto-populate feature, should that also be required.

cheers

Update

Looking at this a little more closely.

I'm overriding the mage/customer/controller/accountController.php :: createPostAction() and I see in the controller the location where the form is processed and populated as a customer entity.

I'm trying something like this

   if ($this->getRequest()->getPost('create_address')) {
        /* @var $address Mage_Customer_Model_Address */

        $address = Mage::getModel('customer/address');

        /* @var $addressForm Mage_Customer_Model_Form */

        $addressForm = Mage::getModel('customer/form');
        $addressForm->setFormCode('customer_register_address')
            ->setEntity($address);

        $addressData    = $addressForm->extractData($this->getRequest(), 'address', false);
        $addressErrors  = $addressForm->validateData($addressData);
        if ($addressErrors === true) {
            $address->setId(null)
                ->setIsDefaultBilling($this->getRequest()->getParam('default_billing', false))
                ->setIsDefaultShipping($this->getRequest()->getParam('default_shipping', false));
            $addressForm->compactData($addressData);


            // attempting to jam vars into address obj
                $address['_data']['firstname'] = $this->getRequest()->getPost('billing_firstname');
                $address['_data']['lastname'] = $this->getRequest()->getPost('billing_lastname');
                $address-['_data']['fax'] = $this->getRequest()->getPost('billing_fax');
            // end 
                Mage::log('createPostAction, after var jam: '. print_r($address, true ) );


            $customer->addAddress($address);

            $addressErrors = $address->validate();
            if (is_array($addressErrors)) {
                $errors = array_merge($errors, $addressErrors);
            }
        } else {
            $errors = array_merge($errors, $addressErrors);
        }
    }

When i log this out:

2012-12-18T01:51:10+00:00 DEBUG (7): createPostAction, after var jam: Mage_Customer_Model_Address Object
(
    [_customer:protected] => 
    [_eventPrefix:protected] => customer_address
    [_eventObject:protected] => customer_address
    [_resourceName:protected] => customer/address
    [_resource:protected] => 
    [_resourceCollectionName:protected] => customer/address_collection
    [_cacheTag:protected] => 
    [_dataSaveAllowed:protected] => 1
    [_isObjectNew:protected] => 
    [_data:protected] => Array
        (
            [entity_type_id] => 2
            [entity_id] => 
            [is_default_billing] => 1
            [is_default_shipping] => 1
            [firstname] => Chirp  // customer firstname
            [lastname] => Anaplex // customer lastname
            [company] => some agency
            [street] => 2345 somewhere dr
            [city] => somecity
            [country_id] => US
            [region] => 
            [region_id] => 44
            [postcode] => 84151
            [telephone] => 123-123-1233
        )

    [_hasDataChanges:protected] => 1
    [_origData:protected] => 
    [_idFieldName:protected] => entity_id
    [_isDeleted:protected] => 
    [_oldFieldsMap:protected] => Array
        (
        )

    [_syncFieldsMap:protected] => Array
        (
        )

)

The form variables are getting passed successfully ( i see them in the log ), but I seem to be unable to insert them into the address object this way. I get the following Notice:

2012-12-18T16:39:39+00:00 ERR (3): Notice: Indirect modification of overloaded element of Mage_Customer_Model_Address has no effect  in /root/namespace/module/controllers/AccountController.php on line 79

If this is "Indirect" - what is the "Direct" method?

Anyone?