Alignment in Flash CS5

Hello all.
First time here. please be gentle.

I am trying to have a simple web site that once published, appears in Safari or Firefox(all latest version) centre stage
My only options in Flash CS4/5 are I think in the publish preview/Html wrapper where the file can appear top left or top right. nothing else

I would really like to have it bang on in the middle of whatever browser page is used and also resizing itself to the browser’s window but i bet thats another story.

I am guessing I need to create an Html file in word with some code???

Could someone take some time to explain?

Kind regards

PlanetDaDa