What happens if you pull up one of teh locks? Does the other one also unlock? What about when you lock your door? Does the passenger's door also lock? When you open the trunk/boot with the key, do the door locks also unlock? When you unlock the car from either door, does the other door also unlock? These are all the features of the power locks...
Maybe you have power locks, but no central locking system.
Edit: The first picture I posted is from a 1998 model, which uses a different shifter and (I think) different transmission.
I guess your car looks more like this:
I see no button there. I repeat my earlier thought: you may have power locks but no central locking.