Google Analytics help (cross-domain e-commerce)

Hi,

I have an existing e-commerce website that uses Google Analytics.

I've recently configured the site to use the e-commerce tracking features in Analytics and it now tracks the quantity and value of orders.

Unfortunately, as our 'thanks for your order' page, which contains all of the tracking info, is hosted on the payment processing domain it appears that the source of every transaction is 'ourdomain.co.uk / referral'.

Ideally I need someone to screen share with me (LogMeIn or something) and talk me through how to set this up properly so that it passes the details between the domains.

I'm sure it will only take half an hour but expect to be billed for an hour minimum.

Thanks,

Sam