Control over the Pay link on an invoice
It would be good to have control of the Pay link when sending invoices. At the moment it returns to the checkout page which doesn't suit every gateway (mainly Sagepay in the UK). I would like the option to return to a basket or billing information page. Sagepay requires fully formed billing info from the referring site, which isn't always available when generating invoices. Returning the invoice to the checkout page rather than the billing info page makes the Sagepay gateway instantly fail.