Here is how my order process worked on a recent site I made...
The basic process is pretty much the same as created by the ecart checkout wizard.
Basket Page (Cart) --> Checkout (Customer adds Billing & Shipping Details) --> Confirm (Review Order)-->Submit Order to Payment Gateway.
take a look at the URL www.blunique.co.uk and go through the buying steps.
Look at the code and see if it helps