flashsite template customization

Have a flash template that uses xml files to create/update each page of the flash site. I need the ability to put some html or php inside some of the pages, for instance i need to add a blog to the site and also want to integrate ecommerce and would like to have these features embedded into the pages rather than popping up as separate pages. The current template is fairly strict on how the pages look and what content can go in. Also need some elements such as arrows customized - this has to be done thru the flash file.