Scale Inner will show as much of the layout as it can without ever showing anything outside the layout.
So, when a device can't show the full layout it will be centered by default.
You just have to set scroll Y to the bottom of your layout.
There are a few other things to watch out for... if you are manually positioning objects, it takes the browser about 0.1 seconds to figure out what its dimensions are. (after that, the dimensions don't change unless you trigger the "Browser - On Resized" event... then you have to Wait 0.1 seconds again.)
You can also use the Anchor behavior to position objects - they will stay in a relative position to the edges they are anchored to...
I made a quick sample which works on my iphone, ipad and desktop: