Negative Issue Parts in BOM (Windchill 10.2)?

I have a module that contains a control panel, so an assembly inside another assembly.

• Module
  • Control Panel
    • (with part I want to negative issue)

Is there a way to 'take away' a part in a BOM?

• Module
  • Existing Part I want to negative issue
  • Control Panel
    • Original Part

The control panel is purchased with the part I want to remove, so I don't want to create two different control panels for a small part that we will take care of ourselves. I tried tying in a (-1) for the quantity, but Windchill doesn't allow negative numbers. Does anyone know of a way I can handle this?

I'm using Windchill 10.2 and Creo 2.0