So the drawing view is referencing an assembly and the named sketch can be found in some parts in this assembly.
You need to iterate the occurrences collection.  In every occurrence you should try to find a PlanarSketch with the required name and then create the appropriate PlanarSketchProxy object.  You need to pass this PlanarSketchProxy object into the DrawingView.SetVisibility method.
 
The following VBA sample code illustrates this approach.
Sub Test_SetVisibility_Sketches_Assembly()
    'active drawing doc
    Dim oDrawDoc As DrawingDocument
    Set oDrawDoc = ThisApplication.ActiveDocument
    'active sheet
    Dim oSheet As Sheet
    Set oSheet = oDrawDoc.ActiveSheet
    'the 1st drawing view
    Dim oView As DrawingView
    Set oView = oSheet.DrawingViews.Item(1)
    
    'reference to the assembly document
    Dim oAsmDoc As AssemblyDocument
    Set oAsmDoc = oView.ReferencedDocumentDescriptor.ReferencedDocument
    Dim oAsmDef As AssemblyComponentDefinition
    Set oAsmDef = oAsmDoc.ComponentDefinition
    
    'reference to some component (here it is the 1st)
    Dim oOcc As ComponentOccurrence
    Set oOcc = oAsmDef.Occurrences.Item(1)
    
    'reference to the part document
    Dim oDoc As PartDocument
    Set oDoc = oOcc.Definition.Document
    'part definition
    Dim oDef As PartComponentDefinition
    Set oDef = oDoc.ComponentDefinition
    'sketch in the part context
    Dim oSketch As PlanarSketch
    Set oSketch = oDef.Sketches.Item(2)
    
    'sketch in the assembly context - proxy object
    Dim oSketchProxy As PlanarSketchProxy
    Set oSketchProxy = Nothing
    Call oOcc.CreateGeometryProxy(oSketch, oSketchProxy)
    
    'make  PlanarSketchProxy visible
    Call oView.SetVisibility(oSketchProxy, True)
    
    Beep
End Sub
 Additional information you may find here
http://adndevblog.typepad.com/manufacturing/2012/06/include-sketches-from-sub-assemblies-in-a-drawin...
 
Proxy objects
http://modthemachine.typepad.com/my_weblog/2009/04/positioning-assembly-occurrences.html
http://adndevblog.typepad.com/manufacturing/2013/07/occurrences-contexts-definitions-proxies.html
 
cheers
					
				
			
			
				
	
Vladimir Ananyev
Developer Technical Services
Autodesk Developer Network
