ScrollView inside absolute layout not working

I'm trying to create something like this:
->absolutelayout
->scrollview with some content
->a label
the scrollview is supposed to fill out the entire page while the label should appear floating on top of the page

I basically tried http://forums.xamarin.com/discussion/comment/62467#Comment_62467
but it seems that without a widthRequest and heightRequest of the scrollView, the scrollView just won't appear

Again, I want the scrollView to Fill the page with LayoutOptions.Fill, but it seems that the absolute layout just ignores the layoutOptions, what should I do??