session lifetime

[everex]

Hi,

could me anybody say, how can I set the session lifetime? I don't think to change php.ini of course, because I have no access to config files. I read on this and other websites, that it could be done via PHP code using ini_set command, but I nowhere saw any concrete example. I tried to use this

ini_set('session.gc_maxlifetime', '36000')

but without succes. If I check it with ini_get, it really returns value 36000 but session expires after default value defined in php.ini which is 1440 secs ;-(

Thanks for help