Creo Process Plan - Adding included assembly items

I'm creating a process plan (work instruction) of a design assembly.  In the design assembly there is an 'included' item that appears in the tree.  Seems the process plan module will not let me select this item for use in one of my assembly steps..  I can 'add' the identical assembly to the step but I'd really like to consume the one that already exists.

I know the process plan module is a niche  and probably gets little use by most but any help appreciated.

Creo 8.0.0.0