Supply & Demand vs MRP Message Detail

I was wondering if anyone has run into this issue and how it was handled. We have an upper-level assembly (Part A) sold on a sales order. Part A is a manufactured item that consists of Part B and Part C. Part B is set up as a phantom that consists of Part D, Part E, and Part F. What I am looking at is Part B and how the components are driven and show up in Supply & Demand along with how MRP processes this demand.
When the order for Part A is entered it will show up in Supply & Demand (F4021) with a planned demand order. After MPS & MRP (R3483) is run it still shows the demand but now shows a planned supply work order to fill that demand. Then if you look up the phantom (Part B) in supply and demand it shows up as demand to supply the assembly (Part A). If you go one step further and look at Part D, E, & F each one will show that they have a demand requirement.
So, we are seeing the lower-level demand in Supply & Demand but why do we not see anything show up in MRP Message detail? All documentation that I have read states that phantom components will not show up until the upper level (Part A) work order parts list is attached.