This isn't really a question, more of a tip for those, like myself, who have been puzzling over why embedding Flash into a template using SWFObject2 (as recommended by the SilverStripe team) caused their sites to give an 'operation aborted' message in Internet Explorer 6.
You simply have to close the <base> tag in the head using conditional comments, so only IE sees the </base>. I found this in the FAQs on the SWFObject site: http://code.google.com/p/swfobject/wiki/faq
Guess I should have looked there first before trying to engineer all sorts of elaborate workarounds!