Google Analytics eCommerce data with payment gateway callback

We use WorldPay as our payment gateway and we've specified the callback URL to be myurl.com/payment.php, however worldpay doesn't actually redirect to this URL, it passes some parameters to it, ie, whether the payment was successful, how much for, etc and then displays the result through a worldpay server.

What I want to do is implement Google Analytics eCommerce开发者_如何学C tracking (instructions found here: http://code.google.com/apis/analytics/docs/tracking/gaTrackingEcommerce.html ). But this requires javascript which isn't enabled on the worldpay server.

I could do an immediate meta refresh to myurl.com/analytics.php which displays, aesthetically the same screen, but is actually on our server, so the JS will work.

The question is, how do I pass the cartID, if i'm using a meta refresh?

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See: http://www.tatvic.com/blog/google-analytics-worldpay-ecommerce-tracking