How to disable file attachments from OAF pages

When the user clicks the attachment link from a web-based (OAF) screen in EBS they see the attached Add Attachment page. How can we change this page so that the users are no longer able to upload files. We are replacing the file-based attachments in EBS with the WebCenter Managed Attachment solution and want to stop users from attaching files, but still allow them to use URL or text attachments. We were able to do this for attachments created from the forms-based pages by end dating the file type attachment item from the list of values, but that only seems