This is the standard order submission to the API.
field : orderID
When an order is created Nuvias creates a unique orderID that has the form:
Typical Sales Order would e.g. SO39609
field : purchaseOrderID
The reseller must submit data in the purchaseOrderID of an order.
The purchaseOrderID can be any text, but it must be unique across all orders, even ones that have been submitted by hand previously. Any duplication found will reject the order with an error and provide you with the orderIDs of the other orders with the same purchaseOrder.
By ensuring that any purchaseOrderID is unique this feature is used as a safeguard to ensure that orders are only placed once. A reseller can ask for this enforcement to be removed, but this will require a business case for justification.
field : shippingMethod
This requires a string from a list of possible shipping Methods that are available on the resellers Account.