Photoshop :: Large Strokes (layer Effect) Uneven At Corners?

I'm using Photoshop CS6, but I've confirmed that this happens on CS4, CS5 and CS5.1 too.
 
When I create a shape (say a simple triangle or such, using the various Shape tools), then apply a large (40px) Stroke Layer Effect to it, the corners of the stroke aren't smooth - they're stepped/jagged.
 
Note how the corners of the stroke aren't perfectly curved, but are made up of noticeable straight lines. The document you're seeing is being viewed at 100%, by the way. The stroke is set to Outside, and is 40px in size.
 
I'm aware of the new native strokes for vector shapes in CS6, and they don't have the problem, but in a certain project I need to combine both the native vector strokes and also the stroke layer effect, so I can't simply use the native strokes instead.
 
I'm also aware that I could use an Illustrator Smart Object with a pre-applied stroke, but that doesn't address whether this behaviour in Photoshop is broken or not.
 
It's been suggested to me that this problem arises because Photoshop applies the stroke layer effect to the rendered bitmap of the layer, not to the vector shape itself, and that's why the problem has persisted for several versions of CS.