Setting HDTV AC3 stream to Dolby Surround Mode for burning onto DVD

[choirislife923]

Here's the problem I'm having...
I've been using ProjectX to demux my .TS files that I captured using my myHD 100 ATSC capture card. After I get the demuxed mpeg2 and ac3 files, I threw the mpeg2 file into MainConcept and got a DVD compliant 480p file, which I then remuxed with the ac3 and authored into a DVD-Video.

Everything seems to go well but when I turn on my 5.1 reciever and switch it to surround mode, I'm only getting stereo.

Now, the AC3 files that I captured are in 2.0 but I know they have Dolby Pro Logic II (tested it out on the same reciever using analog RCA cables), so I have a feeling that someone at the station didn't turn on the "Dolby Surround Mode" flag when encoding. Since I don't want to lose any quality from the already compressed ac3 file, is there a way to enable the dolby surround flag without doing a reencode?

[Krispy Kritter]

Most surround capable receivers will take a stereo source and create the missing channels on their own. You usually just have to turn on Dolby or theatre mode (or whatever your reciever calls it).