how to change gateway without using YaST?

I'm using SLES8. I want to change gateway on that SuSE without using YaST. I've changed the /etc/sysconfig/network/routes with this entry: default: 192.168.1.254 - - But, after I restart the network device, that entry won't work. My routing table still won't change. Which file I should change if i want to change my gateway manually? regards, Agi