Front-end, Back-end and htaccess

[eluser]Sceneshift[/eluser]
I'm not sure the above would work since I'd like http://www.mysite.com/admin/ to act as the root for my 'backend' application.. for example:

http://www.mysite.com/admin/controller/method/

I understand I could have a route setup so anything /admin/ automatically points to admin.php's root controller, but I'd prefer to just rewrite it.