[PHPdev]

I had to edit...

Database:
xcart_customers:
Add b_address2
Add s_address2

xcart_orders:
Add b_address2
Add s_address2

Templates:
register_billing_address
register_shipping_address

PHP files
func.php specifically the func_place_order function had to edit the insert, and update for orders adding the to added fields to the query
register.php

I beleive both php files are in the ./include directory

Let me know if you need more detailed information