Recurring Authorize.net Processing

[gzimmerman]

Using Civi4.5.8, WordPress 4.1.1 and Authorize.net
I understand that an immediate Receipt email does not go out for Recurring payments so we added a BOLD NOTE in the Thank you page about this....
This is frustrating..... Onto another subject....
I do want to get data back to Civi to "complete" the processing for the recurring "Pending" transaction  I understand that I can do this and I see in online documentation there is a Silent Post URL back to Civi for Joomla and Drupal:
Drupal: https://yoursite.org/sites/all/modules/civicrm/extern/authorizeIPN.php
Joomla: https://yoursite.org/administrator/components/com_civicrm/civicrm/extern/authorizeIPN.php

What would be the URL for WordPress?
THANKS.