Debian:使用PHP运行一个新屏幕

I'm currently trying to build a screen manager for my V-Server (running Debian 6.0.6) using PHP.

My script does already show the runnung screens, but I just fail at running a new screen:

webstat.php:

exec('sudo -u root screen -ls',$result);
print_r($result);

Added to sudoers (I know that this is unsecure, but it's easier in the testing phase):

www-data ALL=(ALL) NOPASSWD: ALL

Here is the code I've tried to run a PHP-file in a new screen:

exec('sudo -u root screen -S screenId php /var/www/script.php parameter1=1',$result);
print_r($result);

This just outputs "Must be connected to a terminal.", but using SSH this command is working perfectly.

Next I read about the SSH-command and tried this command:

sudo -u root ssh -t root@box screen -S screenId php /var/www/script.php parameter1=1

That command worked using PuTTY, but when I use this command in PHP it gives no result nor starts a new screen session:

exec('sudo -u root ssh -t root@box screen -S screenId php /var/www/script.php parameter1=1',$result);
print_r($result);

There are no functions disabled on my V-Server. I don't want to write a bash-script which I call with PHP, I want to execute the commands directly with PHP.

It would be nice if someone knows how to fix this problem!