You don't connect the Sony HT to the PS3

It's the other way around. Stuff goes TO the home theater system and then 1 cable goes out to the TV. But sounds like for that one you only send the sound from your PS3 to the Sony using an optical cable and still have to connect an hdmi cable from the PS3 to the TV. That's how I hooked up my PS3 to my receiver. THen you have to go into the PS3 settings and change the audio to optical cable.