[Ruste 318ti M-sport]

Hi Guys, First post on this site after getting my 318ti, have been reading the threads with interest.
my question is does anyone know why i cant swithc my asc off? the light comes on at the dash when the ignition is first turned on but then goes off. i am understand the asc is automatically on whenever the engine is on but i thought you could switch it off if desired (by the green switch) which should illuminate the dase light - this doesnt seem to be the case? does anyone have any suggestions?

thanking you in advance