Can not redirect to logout page

I have built a website integrated with Facebooks latest PHP SDK (3.0.1 i believe). I have had a lot of p开发者_运维百科roblems during authentication. I have successfully been able to login but i'm facing a problem logging out. I do not use any JavaScript. I need everything to be in PHP. When i use the getLogoutUrl below, it doesnt seem to go back to the logout.php in my domain. It goes back to the index.php. Please tell me what i am doing wrong. Thank you much!

$facebook->getLogoutUrl( array(
    'redirect_uri'  => 'http://mydomain/logout.php')
);

as of php sdk 3.0.1 its next for redirection

{$facebook->getLogoutUrl( array(
    'next'  => 'http://mydomain/logout.php')
);}