Change eth0 (wan) IP address

Hello, neighbours and friends...

I would like to know if there is a way to permanently change the ip address of the eth0 interface. It actually has self-assigned IP 169.254.103.111 and I would like to permanently have 192.168.2.2.

I have tried with ifconfig eth0 192.168.2.2 but when restarted, the eth0 IP goes again to 169.254.103.111

Any clue on how to get what I want?

Thanks in advance