sony bravia optical output

my tv is a sony bravia hdtv model: kdl32m4000
inputs, 2 hdmi rear, 1 s-vieo rear, 2 composite video(1 rear, 1 side), 2 component video, (rear), 1 pc(rear), 1 a/c and 5 audio(4 rear, 1 side),

outputs:
1 optical digital audio(rear), 1 audio (rear) and 1 headphone (side).

I have direct tv, but no hd yet. I used s-video to connect the tv and audio cables from the cable box to the in of the reciever, i connected the ps3 using hdmi to the tv and and an optical cable from the ps3 to the rear of the reciever but i get no sound from my home theatre speakers, i only get the sound from the tv.

I need you help, i have been to best buy a dozen times and everytime, i get a different answer and I am confused.

Thank You

Julio Ramos