After the third call to PayPal, we got the answer. Maybe Webassist should document this.
The hidden field value on confirm.php for the return value <input type="hidden" name="return" id="return" value="http://www.yourWebsite.com/checkout_success.php" /> is an OVERRIDE.
In PayPal's setup preferences for Web Payments Standard in the mytools section there is a radio button to enable AUTO return. This must be enabled AND a URL entered into a text field for the user to be returned to.
Now the issue is, if you have multiple websites, you may only specify one URL via PayPal's settings. So the confirm.php value OVERRIDES the PayPal preferences settings. But, you still must have auto return enabled and a URL entered, even if the URL is set to www.google.com.
This will allow you to alter the confirm.php page on multiple websites to make payments to a single PayPal account and then be returned to the specific website after a successful transaction.
<input type="hidden" name="return" id="return" value="http://www.yourWebsite.com/checkout_success.php" />
Hope this make sense.
