AutoCAD Inventor :: Multi-level Structured BOMView

I am iterating through a multi-level structured BOMView and checking to see if the component occurrences) corresponding to each BOMRow are visible or not.  It seems that only assemblies (and sub-assemblies) have valid occurrences where I can check the Visible property.  All parts are skipped (returns False).  My code is below:

Private Function ItemIsVisible(ByRef bomRow As Inventor.BOMRow) As Boolean Try Dim cDef As ComponentDefinition Dim cOcc As Component Occurrence For Each cDef In bomRow.ComponentDefinitionsFor Each cOcc In cDef.Occurrences If cOcc.Visible Then Return True Next cOcc Next cDef Return False Catch ex As ExceptionReturn False End Try