If the robots.txt is static you could also put the file directly to app/webroot.

Nice tutorial thanks. You just saved me the time of figuring all of this out for myself.

Important to add these two properties in your controller to make it work:

var $uses = array();
var $components = array('RequestHandler');

So this way you won't get errors like:
- Error: Database table seos for model Seo was not found.
- Undefined property: SeoController::$RequestHandler

Gr, Paul Edenburg