Sending an attachmed to a custom field


RT supports custom fields including custom fields with file uploads. You can also add files to a ticket as well by simply replying to a ticket (by mail) and then attach a file to this mail. When a file/attachment has been added to a ticket by for example a user who has replied to a mail, is it possible to update such a custom field and set the content to that attachment without having to download the attachment first locally and then uploading it again to this specific custom field?