For Distributors and Agents who resell product, there are usually some services or fees charged to the customer. These types of fees require a vendor entry in OASIS but since there is no actual product being ordered, it is not necessary to create a vendor order. Frequently, the manufacturer would be the client's name or other alter ego.
To set up the manufacturer, open the correct manufacturer entry in OASIS and go to the Terms Tab. Look at the Order Terms Tab and select "Entry for Invoicing only (no Vendor Orders)