HDMI tech issue...

[dv8pdx]

Ok, I've done my little searching and so far have found nothing really towards my question.

I bought a Plasma with built in 5.1 digital surround (yes I will upgrade to a reciever one day) and it only has HDMI 1.2 - when I use my PS3 via HDMI, the 5.1 digital indicator doesn't light up, which it does with digital optical. Now I have 3 HDMI inputs and only 1 optical input and I want to add HD-DVR via HDMI too... the tech guy at Vizio says I cant get digital 5.1 to the TV via the PS3 because the PS3 is HDMI 1.3a and the tv is 1.2 - is this true or does he not know what he's talking about. I thought 1.3 had all the same features as 1.1 and 1.2 with Dolby TrueHD and DTS HD-Master Audio upgrades (not worried about the upgrades to video at the moment). So if this is the case, shouldn't the PS3 still send a 5.1 digital signal to the TV?

PS3 HDMI OUT 1.3a via HDMI 1.3a cable to TV HDMI 1.2 input

Would love any help before I banter back and forth with this Vizio tech dude.