Hello Oscar:
First at all, you should configure a BOM Application to do what you want. Be carefull and configure a new Sel ID and BOM application to avoid impact in production order creation.
In SPRO you can do this in Alternative Determination Section
1. Define Order of Priority for BOM Usages - OS31
Create a new SelID, and indicate Selection priority 1 and BOM Usage 2 Engineering/design
2. Define application OS30
Create a New Application and assign the SelID created in previous step.
After that , you can test in CS12 (Explode BOM Multilevel) using the new BOM Application. Finally BOM application should be a parameter in your Z screen.
I hope this help you.
Kind regards,
Milton