Wordpress and Vanilla Inetgration on different subdomains (log out problem)

Gozlingo

Hi, I've got Wordpress installed on http://www.riskcollective.com and Vanilla installed on http://community.riskcollective.com. In order to get the logins working between the two, I changed the cookie domain setting to '.riskcollective.com' which seems to work fine. My only problem is that signing out doesn't work - it doesn't clear the cookies. I'm using the WordpressAuthenticator.php class and made some modifications in there to make it work between subdomains. I made changes to all setcookie functions and added in the 'domain' argument putting in '.riskcollective.com'. I also did this in the DeAuthenticate function (which I presume clears the cookies out on sign out), but it doesn't seem to work. I'm really confused though as I put an 'exit;' statement in the DeAuthenticate function to see if it was even being called and the script doesn't stop executing so I'm not sure if it is even being called. Does anyone have any ideas?? Thanks, Oli