Ok, it looks like what you will need is a PostProcessing Method Directive on Erp.BO.Quote.CreateOrder
In there you can access your UD field in QuoteHed:
Get SO uses the Erp.SalesOrder.GetByID with the orderNum variable that is in the CreateOrder definition. You can use this to create a DataSet variable that will be returned with the sales order information.
The Set SO_UD is used to set the Sales Order UD field to the QuoteHed UD field. Remember in a post processing there is no added/updated … rows.
So the Properties of Set SO_UD would look like:
Set the dsSalesOrder.OrderHed.DecorType_c field of all rows to the dsQuoteHedRow.DecorType_c
The Save SO uses the Erp.SalesOrder.Update with the DataSet created by the Get SO block.
That’s a real basic look at the concept I think you’re trying to get to.