I can't see any previous posts about this but sorry if it's already been covered. I've created ISOs for a few of my Blu Ray disks but can't get them to play through Windvd. My HD-DVDs work fine. Also, the physical Blu ray discs work OK just not the ISOs. Blu Ray works fine through PowerDVD but I can't get 5.1 sound through that it only ever outputs 2 channel - even on passthrough!
I don't think the mounted Blu-ray ISO's will work with WinDVD. If you are using AnyDVD I think that function only works with PowerDVD. Also if you are using the version of PowerDVD that came with your Blu-ray drive chances are you will have to upgrade to get the "full" surround sound option. I have a Lite-on BR drive that came with the PowerDVD software and that was the case with that version.