Not quite true; if you havent got the switch it does not mean you dont have ESP. You just cant turn it off.
To make sure if you have it or not, turn the ignition key to position 2 and check whether the light in your dashboard comes up.
If yes: you have ESP and cant turn it off.
If not: you dont have ESP.
Theres a series made in 02 that dont have the switchable ESP, though.
Cheers
Sandro