Please elaborate your new business process. Without knowing the detailed process, it will be difficult to address your queries. RTP materials (pallets, containers, cylinders, etc) belong to a special stock (M) belonging to vendors and not you and hence not valueted. Like consignment you can not transfer RTPs into your own stock. You can not use all movement types for RTP and 101 movement type is not supported with special stock type M, hence it may not be possible to create PO for them bacause while doing GR along with 101 of the purchased material you post a 501M movement type for RTPs.
Explain your business process and forum members will come forward with suggestions.