We will start off with a standard stair by component.
When we enable the <Above>Up Arrow checkbox, click on Apply and OK, our Stair Path will now continue past the Cut Line, and terminate with an arrow at your last tread.
To change stair path representation at the landing corners to a Curve, select the Stair Path and edit its Type Properties. Under the Graphics area, you will see a Line Shape at Landing Corner property. Change this to be a Curve.
Quick and easy, isn't it? There is one drawback to this method though. Once you convert your landing to a sketch-based element, your stair path will not have curves at your landing corners. So the workaround is to draw your curves using detail lines (Indicated in red)