Migration of HR Helpdesk request to Cases

We are trying to move the service requests from HR Helpdesk to Cases to make better use of both the modules. The move is related only to sensitive service requests (formal casework). We are able to map and move service request details to Cases and also move across attachments by use of action action plan. But there seems to be no way of moving across the messages (specially when there is a chain of messages between agent and customer) . Same goes for the attachments related to messages. Can you please guide on the feasibility of this task