Moving Drupal to subdirectory/ Clean URLs/ Admin page

Hi,

There is the need to make a site available from a subdirectory.
e.g Move the site from www.test.com and make it available only under URL www.test.com/newsite. The latter URL must be shown only.

Clean URLs are enabled and everything works OK, except I cannot longer access the admin page. When i point the browser at
www.test.com/newsite/user the page serves OK. I enter the credentials and when i click login the broswer redirects to:

www.test.com/newsite/newsite/user

It duplicates the "newsite". and it shows that Im not longed in...

I have set in .htacess the following

RewriteBase /newsite
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

i have tried modifying the base_url in settings.php but with no luck...