Background Resize 100% (mask._width Problems)

Hey There!

I´ve done a background that checks Stage.width and mc._width and then make a 100% Background MovieClip, it works ok, it´s attached here as “resize.fla”.

My problem is to make this background 100% using a Mask inside the Background.MovieClip, anything put inside the movie affect the ._width and bug all the code, showing the background with the mask ._width.

What i want to do is to show only the background and everything “inside” the mask layer, i´ve tried everything, search foruns, help files and can´t got this to work.

I´ve tried to make a diference between the widths, something like.::

difX = bg._width - mask._width;
difY = bg._height - mask._height;

and then on resize use

bg._width = bg._width - difX;
bg._height = bg._height - difY;

But no Sucess, the mask is inside the Background MC, and even outside the code does not work.

I´m sending the files here, if anyone could help me i´ll be very thankfull, this thing is really taking out my nights,

resize.fla works Ok (No Mask Inside) and
resize_maks.fla has the “bug”.

(The Attached FLAs have a single color background because the file limit accepted here.)

Thanks for any help.