Promotion request is another vehicle that allows component parts or documents promote from initial state to their released states. In a way, customers see Promotion Request also as a kind of change object. All the change objects like ECN, ECR, Problem Report, Deviations and Waivers allow adding, editing and removing attachments through create and edit UI. But Promotion Request object is an exception for some reason in not allowing attachments in create and edit UI. But this exception is only at client layer as Promotion Request implements content holder interface and through APIs in the back end, files can be attached to Promotion Request object.
Please add the UI functionality as well to allow users to add, edit and remove attachments on Promotion Request object through UI.