Adding components to simplified representation

I've got an OTK JAVA Free app working to create simplified reps with a method as shown below. I cannot get Creo to show any components in this simplified rep.

The method should accept inputs as a Solid (the assembly that the simp rep is to be a member of), an integer sequence (I only want to show a single component, so only the index 0 is used) and an integer (only used for messages, denotes it's location in a sequence). 

The method should create a new simp rep with the default action to exclude all components, which it does successfully. It should then add the component with the feature number that is index 0 in the integer sequence as a master rep. This does not happen.

So my question is, what should I do to the below code to make the component identified in the "is" integer sequence as index 0 appear as a master rep in the simp rep called leafsimp? At the moment I just get a simp rep with all components excluded.

In the below, printMsg is a method that just calls System.out.println("App name" + inputString); I've used it to extensively log where the code has got to into a text file to help with debugging.

Thanks in advance for any assistance!

private SimpRep newSimplifiedRep (Solid assembly, intseq is, int i) throws jxthrowable {
	 
	 //1. Create new SimpRepInstructions object
	 printMsg("Attempting new simp rep insructions: " + i);
 	 CreateNewSimpRepInstructions simpInstruction = pfcSimpRep.CreateNewSimpRepInstructions_Create("leafsimp"); 
 	 printMsg("Attempting to create a SimpRepItems array: " + i);
	 SimpRepItems leafComponents = SimpRepItems.create();
 	 
 	 printMsg("Setting up Simp Rep: " + i);
 	 
 	 // taken from https://www.ptc.com/en/support/article/CS281859
 	 
 	 //3. Initialise a pfcSimpRep.SimpRepItem object for the item by calling the method pfcSimpRep.pfcSimpRep.SimpRepItem_Create? 
 	 //SimpRepCompItemPath itemCompPath = null;
 	 printMsg ("Adding component " + is.get(0));
 	 SimpRepCompItemPath itemCompPath = pfcSimpRep.SimpRepCompItemPath_Create(is);
	 SimpRepItem leafComponent = pfcSimpRep.SimpRepItem_Create(itemCompPath);
	 
	 
	 // Include component as Master Rep
	 SimpRepInclude includeAction = pfcSimpRep.SimpRepInclude_Create();
	 leafComponent.SetAction(includeAction);
	 SimpRepAction leafAction = leafComponent.GetAction();
	 printMsg("Component Added as: " + leafAction.toString());
	 
	 //4. Add the item to the pfcSimpRep.SimpRepItem sequence. Put the new pfcSimpRep.SimpRepInstructions using pfcSimpRep.SimpRepInstructions.SetItems
	 printMsg("Attempting to add the SimpRepItem to the SimpRepItems array:" + i);
	 leafComponents.set(0,leafComponent);
	 printMsg("Number of components in Simp Rep: " + leafComponents.getarraysize());
	 
	 printMsg("Setting default action to exclude");
	 SimpRepActionType simpAction = SimpRepActionType.SIMPREP_EXCLUDE;
	 
	 printMsg("Adding default action to simp rep instruction");
	 simpInstruction.SetDefaultAction(simpAction);
	 
	 printMsg("Creating Simp Rep leafSimp");
 SimpRep leafSimp = assembly.CreateSimpRep(simpInstruction);
 
 printMsg("Activating Simp rep");
 assembly.ActivateSimpRep(leafSimp);
 
 printMsg("Getting instructions from Simp Rep");
 SimpRepInstructions simpInstructionLeaf = leafSimp.GetInstructions();
	 
	 try {
 printMsg("Adding item to Simp Rep Instructions");
	 simpInstructionLeaf.SetItems(leafComponents);
	 
	 printMsg("Activating updated Instructions");
	 leafSimp.SetInstructions(simpInstructionLeaf);
	 }
	 catch (Exception e) {
		 printMsg("Failed to set updated instructions: " + e );
	 }
 
 //regenerate model
 printMsg("Regenerating");		
 RegenInstructions regeninstr = pfcSolid.RegenInstructions_Create(false, true, null);
 assembly.Regenerate(regeninstr);
 
 // return to calling method 
 return leafSimp;
 }