Problems resizing an UILoder

I have a little problem and i don't know how to solve it. I have a UILoder with an image that i resize when it hits Photogram 30 of the movieclip.

I want Card MovieClip to be resized so that it replaces PositionCard (setting it over PositionCard itself), so i put the width and length same as that PositionCard, in the next way:

MovieClip(root).Card.Card_mc.setSize (MovieClip(root).PositionCard.width, MovieClip(root).PositionCard.length);

The first thing i meet is that the inspector doesn't let me take the second argument: MovieClip(root).PositionCard.length. It expands the new Card length to a larger size (very large, indeed).

The second problem i see is that the Card doesn't take the position of PosicionCard. When i fix the "length" problem with...

MovieClip(root).Card.Card_mc.setSize (MovieClip(root).PositionCard.width, 155);

... (because i have seen that PositionCard has that length in Properties), it sets Card_mc a little misplaced from where it should be. I mean, it should be over PositionCard and it is a little on the right and down from it.

So, i would like that if there is someone that know how to fix it, would tell me, because i can't fix the second problem, and i understand that there should be another way to fix the problem of PositionCard.length better than looking for the lengths of the MovieClips i want to deal with.

Thanks beforehand.