Apache supports a parameter string as well, you just have to pass it to the html file itself like this:

somefile.shtml?param=somevalue¶m2=somevalue ...

As an answer to the original question... I believe SSI is the way to go. From what I understand you'll just need to remove the beginning tags from the script you create. Another way to do it would be to use HTML::Template (availiable from CPAN). I often mix both HTML::Template and SSI to do the very same thing you are doing but not have any HTML code inside the script itself.