QML and masking an Item with another Item

What I propose is the possibility to mask an element with another element. This is something similar to mask implementation in Adobe Flash.

You can see a demo here: http://www.entheosweb.com/Flash/masking.asp to make an idea about this feature.

I also tried to create something with current version of qml, as you can see on this forum thread: http://developer.qt.nokia.com/forums/viewthread/1020/ but there are some inconveniences such as animating the items.

in flash is implemented something like this: item1.setMask(item2);