Same PayPal account on multiple websites

[lat9]

I've got two sites that (kind of) share the same PayPal account -- using the PayPal Merchant Services (www.paypal.com/mts, 888 215 5506) "parent-child" account concept.

Essentially, I started out with a verified PayPal account that links back to my bank's checking account. I added another PayPal account as a "child" of that account, so that the linked banking account is used for both. The "child" account sends any funds it receives to the "parent" on a daily basis.

[DML73]

Thanks for the suggestions. I now found why I am getting the "ReturnURL is invalid", its because I have changed:

define('HTTP_SERVER', 'http://www.mysite.com');
define('HTTPS_SERVER', 'https://www.mysite.com');

to:

define('HTTP_SERVER', '');
define('HTTPS_SERVER', '');

in /includes/configure.php

I did this in order to be able to direct my "multi-domain/language on same server site" to the correct domains/languages. Anyway, I guess PayPal needs the "define('HTTP_SERVER', 'http://www.mysite.com');" statements. Im wondering if there is another way of telling PayPal what domain to use??