I am having similar troubles as most of you seem to be having, but my circumstances are slightly different...
First off, I live in Morgantown, WV and my SA 8300HD is through Adelphia, however I cannot get it to work in Dolby Digital either.
From what I can tell, when you guys are using component to input your video, it lets your coax and optic audio outs work correctly with DD, where if you are using HDMI it makes those ports use 2 channel L/R.
I do not have an HDTV, nor is my TV new enough to use component video plugs (I know old, but hey, it happens :/), therefore I'm reduced to S-Video or composite. Currently I have my box hooked up with the composite cable running through a Pelican Selector Pro, and a coax cable running directly to my Pioneer receiver. However, when I watch anything my receiver says Pro Logic II instead of switching to the Dolby light as it should when receiving a true DD signal, showing me that it is not being sent in DD correctly, which I see now isn't only my problem.
Is there any way to fix this aside from using Component cables only? Maybe try an S-Video cable instead of composite? (I know that's a given anyway, I just haven't had time to get an S-Video cable yet, I just got this box top yesterday). Has anyone has luck with DD using the S-Video or composite ports? I just registered for these forums as well, but from what I have heard and can tell, this is the best possible place to ask for help. Anybody have any suggestions?
Thanks so much in advance.