public class CustomTreeListView : RadTreeListView
{
	protected override AutomationPeer OnCreateAutomationPeer()
	{
		return new CustomTreeListViewAutomationPeer(this);
	}
}

public class CustomTreeListViewAutomationPeer : RadTreeListViewAutomationPeer
{
	public CustomTreeListViewAutomationPeer(RadTreeListView owner) 
		: base(owner)
	{
		var methodInfo = typeof(RadTreeListViewAutomationPeer).GetMethod("GetItemPeers", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
		methodInfo.Invoke(this, null);
	}

	protected override List<AutomationPeer> GetChildrenCore()
	{
		var frameworkPeer = new FrameworkElementAutomationPeer((FrameworkElement)this.Owner);
		return frameworkPeer.GetChildren();
	}
}