Validating html generated by flash

Now I have stucked into validation. It may be nerdy with w3 and all that, but I really like the idea of some ISO-like standard for the web.
There’s actually no problem getting html pages validated, but most of the web contains errors and work fine anyway.

The thing I wonder is: What doctype (DCD) is the html file that is generated by flash? For example, w3’s validator says there is no attribute “LEFTMARGIN” and there’s no tag such as <EMBED>. Of course there is, but not in that DCD. (flash generates no DCD)
Is there a way to get around this an make a tidy code? Should one bother at all?

Check your sites here (or check w3 itself!)