when you want to fake an ajax call, that's because your server's web service is just not ready yet, and whenever that web service is ready, switching back to it should cost nothing..
with jquery.ajax.fake you simply write pure jQuery ajax call, with only one extra property fake: true
include jquery.ajax.fake.js script into your markup, and create webservices.fake.js to handle fake ajax calls
<script src="jquery.ajax.fake.js"></script>