Using models with Scriptaculous's AJAX

[eluser]tokyotech[/eluser]
I'm using the Flickr style in-place editor from Scriptaculous.

Code:

// javascript
new Ajax.InPlaceEditor('elementId', '/saveInfo.php');

So after someone clicks save, the form value is sent to saveInfo.php via $_POST, and that file is supposed to save the value into the database.

How would I be able to do this while being friendly with CodeIgniter's MVC? Shouldn't I be calling some function in one of my models? How do you simultaneously load the model and call one of its methods, while fitting inside this Scriptaculous function call?

My directory structure:

Code:

projectName
   + scripts
      * ajax
         - fileInPlaceEditorShouldCall.php
      * usingScriptaculous.js
   + system
      * application
         - controllers
            ~ thisPage.php
         - views
            ~ viewThatsIncludingUsingScriptaculousJS.php