Someone I know has his Internet Explorer configured to use MSXML 6.0 when parsing XML files (and he is apparently configured with side-by-side mode). I would like to figure out how he did this, but I've not been able to replicate it. I also can't find information on how to even configure IE's default XML parser.

Note, I'm not talking about specifying ProgIDs in the page being loaded.

Anyone have any ideas? I can't find a single bit of information on how to achieve this.