Hi Jim,
I have done this stuff in semizone.com, although that was ACS 3.4. But I think Bart has ported this e-commerce ver to 4.5. I think what you should also take note of is that the shopping cart and ordered items are in the database. From what I remeber shopping cart items are retrieve by the user_id. And the order items are from order_id. You can skip or add pages as long as you make sure the db has the correct info as Bart has advised.
I think its not difficult to change the flow. But changing what happens on the items is a different matter. Anyway most of this info are ACS 3.x based, but I think some still applies. Good Luck.
