no 5.1 surround sound coming out of HDMI from PS3

[natieamwong]

Hi, I am new to this site.
I have a problem and really need help. I called Sony technical support but they can't help me and also hung up on me too.
I have a 52" Sony TV, KDL-52W3000, Home theartre system Sony DAV-IS10, PS3 and HD-DVD player.
I used HDMI cable to connect PS3, HD-DVD player to TV (TV has 3 HDMI inputs and 1 optical output) then I used optical cable to connect the TV to Home Theatre (this home theatre DAV-IS10 has only 1 optical input) then I don't receive the true 5.1 surroud sound from that optical cable.
Do you know what is the problem? Why can't I get the DTS, 5.1 Surround sound?

If I connected the optical cable directly from PS3 to Home Theatre then I got the surround sound.

I have looked at the manual, I found some interesting info here it is
"HDMI IN 1/2/3 : Video 480i, 480p, 720i, 720p, 1080i, 1080p, 1080/24p / Audio Two channel linear PCM 32,44.1 and 48kHz. 16,20 and 24 bits, Dolby Digital.
AUDIO (HDMI IN 1 only) : 500 m Vrms (100% modulation)/Impedance : 47kilohms."

You will see that they say, "Two channel Linear PCM" so that mean it won't carry 5.1 surround sound right? what about "Dolby Digital", is it a 5.1 Sourround?????

It is very frustrated...really need help.....thanks in advance.