Are they added by a user at a user step in the workflow or when you first initiate the form.
If they're added by a user at a user step in your process, you can use the "Output Attachment" property of the "Attachment and Notes" tab to store them in a list.
If they're added when you first initiate the form, we'll have to use some script in the script service to extract them from the task.
Jasmin