Set the registration of duplicated MCs?

Hi, I duplicate an empty MC (mr dupeMC) then loadMovie an external swf (Alien baby). I want mr dupe MC to scale 50% to 100%, from the center, as Alien baby loads inside him…

Old mr dupe MC can scale just fine, but cause loadMovie makes the registration top left, he swells to the right and down, not from the center like I want.

Is this making sense?

I can get around it by writing this in Alien baby:

_parent._xscale = 50;
_parent._yscale = 50;
onClipEvent(enterFrame) {
if (_parent._xscale <100) {

(no I don’t understand the maths, but it seems to work okay)

It would be much easier (and less maths) if I can set Alien Baby’s _x and _y so mr dupe MC’s registration is in the center of Alien Baby.

Any ideas?