Resize dynamically sprites/shapes

Hi all,
I’ve been working on a project based on a flipbook in flex.
I was asked to develop an “highlighting” system, so that an user can highlight bits in the page, and then it can be loaded inside the pages of the flipbook.
The problem that I’m facing now is how to scale the highlighted parts in the page: I explain it better…

I save the marked part with some simple line (in the admin area):

pencilDraw.graphics.moveTo(x, y);
pencilDraw.graphics.lineStyle(pencilThickness, activeColour, 0.5, true, “none”, capsstyle);

but when I load it in the page (in the public area), when the book gets resized according to the windows resolution, even if I try to scale the Canvas or the Sprite containing the graphics, nothing happens… the lines get all kind of flashy, and the size is always the same. Tried to change the width, the scaleX-scaleY, but just nothing.
I don’t really want to repaint the all thing every time the book gets resized.
Do you have any other solution for my problem?