soundless locking

I there

just a query on the alarm and locking of the box, on my previous 2.5 97 box i had a sound when locking or unlocking the car but on the S it is non existant, except if something is left open (ie central box or boots).the only thing that happens is the lights flashing.

i remember on my BMW i was able to change the tone of my alarm locking system, is this possible on the boxster? and where to look for it