3rd Party Sales - How do we set up to have Purchase Reqs show in MD04

We are trying to set up for 3rd party sales, where we will take a customer order and then send a requirement to a Vendor for fullfillment. The Vendor will ship directly to the Customer. So no inventory will be in our system, but our users are used to seeing any kind of request in the MD04 - Stock/Requirements List.

We are using Item Category TAS and Schedule Line Category CS and the process is working fine. But the users would like to see it in MD04, even if we are not physically handling the product.

I've taken a look at the MD_CHANGE_MRP_DATA Badi to try and make it show, but the records are not in the VBBE table when the sales order is entered nor are they in the VBBS table for the purchase req / order side.

Any suggestions on how to accomplish this?