Vxid in an avi container supports AC3 5.1 in DVDFab. Been using it for a couple months, well before Version #5. I'm using an xbox, but the xvid format is the only mobile format in DVDFab that I've found that supports 5.1

Can you use DVDShrink to strip the credits and then use DVDFab to encode?

I don't have a PS3, of course, but I was just throwing that out as a possible solution. I know I spent a huge amount of time looking for a solution when I started storing movies on my server.