Attaching a MC to a dynamic text field

Hello all, im wanting to attach a movieclip to the bottom of a dynamic textfield (autoSize = ‘left’) that uses an XML file of an un-predetermined size. Which is where the problem lies for me…

i tried this simple code first - container_mc._y = comment_txt._height + 10; thinking it was a simple _height; issue - but to no use. So I was wondering whether using attachMovie would be the way to go? maybe something like:
container.onEnterFrame = function() {
this.attachMovie (“container”, “comment_txt”, {_x:0, _y:-90});
}
which also probably well off…

then i wondered does it need a stage listener to know the size of the textfield?

i know i should know this and should be quite simple, but my minds frazzled - please help :wink: