I've been using Flexi cart with PayPal WPS and am using Instant payment Notification (IPN) to update orders once the payment has occurred. I'd like to use this opportunity to empty or destroy the user cart. Of course, the IPN callback is not the user session, so can I use the cart id to do this? There doesn't seem to be a method of using the cart id for this purpose? It's easy enough to include the id in the custom field that IPN returns. Otherwise, the cart is left to expire - or - if the user returns to the site from PayPal, it can be emptied then, but only if they return to the "success" url (or perhaps something more complicated to empty it from any site page).
