Routing issue

[eluser]Unknown[/eluser]
Hi All,
i am developing one application

where their will be two site
one

http://localhost/ci-acme/

and one admin section

http://localhost/ci-acme/__admin__


i am planning for dynamic page for normal section therefore i have changed the route.php

$route['(:any)'] = "maincms";

but now admin section is not opening.

than i changed this setting

$route['__admin__/news'] = "__admin__/news";

than this is coming
http://localhost/ci-acme/__admin__
but
this is not coming
http://localhost/ci-acme/__admin__/content

please suggest the way.

Regards
Anil