In the download there was no ssi.php file as there was with 2.1.7. Is there still a way to be able to do this?

You can use the 2.1.7 file really. :)

Well, I would do that, but now I can't download 2.1.7.....so is there anyway to include one in the 2.2 package? After all, the website DOES advertise being able to do SSI, or is there some other method that I don't know about?

The 2.1.7 file does not work with 2.2. It errors with a IPB Driver message.

Only if you are on MySQL 5 strict (to my knowledge). I'm looking at grabbing a copy for the next release of 2.2 however.