make a new scene layer and then make sure it is unchecked with it's scrollable property. Then put any actor you want to be in the HUD in that layer. You can find the scene properties where you add the layer in the scene editor and then by pressing the scene button at the top of the window. At the bottom of the pane where the actors were is an add button. Press that and make sure you drag it above the background layer.
I think if you drop an actor into it goes to the top, but if not you can just drag it to the top of the list in scene layers. If you get to the point where you want to select and actor and it is below something in the scene and you don't want to move anything crucial by trying to select it with the most, you can select it by touching it in the scene layer list.
Comments
Hope that helps
kipper