I have seen a number of requests on how to get the attachments out of a task before the task is assigned to a user and how to add attachments to a task. Well your wait is over, I have the pleasure of introducing TaskAttachments custom component, which does exactly what you have asked for- Add attachments to a task, and gets task attachments .
I have written a simple process using the custom component. I created a process which triggers every time an attachment is added to a task(in workspace in the attachment tab). In this process, I get the taskID of the task,and pass it to the getTaskAttachment service of my component. This gets the list of attachments for the particular taskID.
Click the link below to get access to the components, which are in a PDF file