Lizard, that’s the problem (FURLs). In ordrer for my tip to work, you HAVE to have FURLs enabled. By default, MODx builds site URLs like:
yoursite.com/index.php?id=NNN
Where "NNN" is the page ID of the page being viewed (as stored in the database).
When FURLs are on and working successfully, you can call the same page via the following additional methods:
mysite.com/NNN
mysite.com/NNN.html
mysite.com/NNN's-alias
mysite.com/NNN's-alias.html
FURLs when accessed via the MODx method of referencing pages ([~NNN~]) will always first try to use the page’s alias, then will fall back to the document ID, and then append ".html". By naming your files in the alias with a custom extension (not really) you get the workaround of taking advantage of the NNN’s-alias (wihout the appended .html).
For what it’s worth, I’ve not been successful in getting URL rewriting working in IIS, but have never run into any issues on *nix servers running Apache with mod_rewrite. Hope this helps.