So your goal is simply to adjust the SWF to be presented at a different size in the browser? Usually you adjust this in the HTML. When you publish as SWF format and you use the HTML option you get an HTML page that contains code that presents the movie. The code contains pixel values that match the project resolution. As you stated you are already hacking the code to make things work, it would seem that all you need to do is amend the values in the object tag.
Typical code in HTML page looks like this: (Click image for larger view)
So you would amend those values to match what you wish the new dimensions to be.
Be forewarned, however, that this may have an unexpected impact on the quality of the Captivate movie.
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