Understanding shipping and totals...

Hi,

I'm trying to integrate with an unusual payment method in that *all* the customers details are provided by the payment provider (think e-wallet type system) and as such there is no 'order' at the time the checkout button is pressed.

I have put together a simple module which receives this callback and creates the order including looping through all the totals and creating an order with $this->model_checkout_order->create($data).

I can't work out how to get it to consider the shipping method however, I've tried manually setting the value of $this->session->data['shipping_methods'] before calculating the totals, but it still doesn't take shipping into account.

There are only two shipping rates - free or flat and I'm happy to code the hard condition for this (free over a specific value) for now to get this working ... a 'proper' module will be in the works after I get it working but it's tricky knowing what to set country and zone ids to when the address isn't known until the checkout completes - for now i'm just setting them to the store's as the store ships to the UK only.

Any advice that can be offered would be much appreciated.