We've added the code to all three required files:
include/register.php
include/address_book.php
skin/common_files/customer/main/register.tpl
It now registers the customer's address with the address book during registration, but while a customer is logged in and they go to view the "My Account" page, the address fields are missing, and it shows this section (see attached photo also):
Code:
Billing address
Save as a new address
Update existing address
Ship to a different address
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