Thanks to senocular AS2 DashedLine.as which was easily converted to an as3 version DashedLine.as for as3 we can draw dotted lines and curves with actionscript. This left me with the task of using the quadratic drawing tools (no i didnt add a cubic curveTo to the Dashed line class) to draw circles (or quarters of circles, for the curners), which isnt the easiest, but i'll spare you the details and simply say, its done!

Using Draw.curvedBox(obj, offsetX, offsetY, width, height, cornerRadius) we can draw into any graphics object (whether it be a normal Sprite.graphics or a DashedLine Object). This is essential as the Dashed line tool doesnt actually give us a fill, so we might need to draw a normal shape for the background.

to draw a curved corner box with a fill, or solid outline, send in mc.graphics as the first attribute (or just the mc in as2)

So we can now do a box with curved corners in either AS2 or AS3 and in dotted or normal... phew!