Time session

Hello,

I'm trying to change the session time on my 1.6.1 version of elgg, but I can't. I tried to change the php.ini file, the httpd.conf file, add a line at the top of the start.php file of the engine folder, and I tried to add a line to the .htaccess file.

I did those changes one by one, but it doesn't work, so i did those changes all in one try, but doesn't work too. 

Does anyone has a idea in order to resole that ?

Benoit