Flash and CMS: Workflow

Hi, I’m designing and creating my first flash-site and would like to hear what others start out with in a flash project like this.

I have designed the site and drawn up how everything is going to work together. Where I will need text fields, images movies and so on. Now I’m wondering what is more efficient:

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[*]Start developing the site in flash, then later configure the CMS to fit my flash.

or
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[*]Configure the CMS that will output the XML-files (in my case MODx), and then develop the flash.
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Regards