I’ve added a step at the end of the Magento one page checkout process. After the user hits “Place Order”, this step appears.
I’ve disabled the $result['success'] = true; so it shouldn’t redirect, but something (after a pause) redirects to checkout/cart and I can’t figure out what JS function is responsible.
Edit: It is possible it’s being redirected to checkout/onepage/success, but that’s bouncing it back because I’ve disabled too much.
Put a event observer for event ‘checkout_onepage_controller_success_action’ and add whatever logic you want in there.
In case you happen to be unfamiliar, here is a tutorial of how to add a event observer: http://www.magentocommerce.com/wiki/5_-_modules_and_development/0_-_module_development_in_magento/customizing_magento_using_event-observer_method