Attachment download only with login?

Does anyone know if there is a way to only allow a customer to download a file if they are logged in? I know I can set an attachment as part of a membership, but the problem is the attachment tab does not show up, so there is no way for the customer to know there is a file available to download. Ideally there would be a link and when they click it they are prompted to register. That way I can build my database from the attachments.

No direct answer to your question, but this is a great idea!