Scott, I came up with a way to embed SSI in any HTML page, I use it for banners but it could so a counter. Basically based on browser sniffing, it creates an <IFRAME> for MSIE or an <ILAYER> for NS. These encapsulate an SSI page. The write-up is here [4geeks.com].
My main reasoning for doing this (at the moment) is for placing the traxis counters on my site. FP doesn't have any issues with renaming the file extensions (that I know of). I could even go for changing the .htaccess file. The problem is FP keeps treating any SSI it sees as true, "let's show this to Mr. Browser", text. Of course Big Brother Monoposoft offers up no info, patches or anything else about it. I'm in the process of transferring everything over to regular ole html pages, but was looking for a really quick work around to get me by for a few weeks. I don't know that the one in your link will do the trick here. I could be wrong, though.....happens all the time!
No, it wouldn't work for page-by-page tracking such as traxis. (well, it would work, but it would require too much setup for a large site) It would work for code that applies across an entire site or in large zones.