I add the same question and finally built a trick. I increased the size of the vertical size of the drop target (called resize target), so my finger is still inside it when the ghost/shadow reach the "bottom" of the initial (not rescalled) target.

To work properly then you should handle the position of the other elements in your page using negative vertical margin, to rise them and cover the extra size of the rescalled target. Moreover (I used a div as the target), I filled my div with a backgroud image that have exactly the size of the initial one using the 'background' style css property : background: no-repeat url("images/bkgdrag.png"); background-size: 72px;

I hope someone will find it useful!