AC3 audio problem with Nerovision Express

I posted this a week ago in the transcoding section. It got 70 reads, but not one reply. I’m hoping that I’ll have more success in this forum.

I have a DVB Satellite card and record movies with AC3 audio. The format is limited with these Sat cards. Many times, you’re forced to record in a 544x480 resolution. I’m in NTSCland, so this makes it hard to convert the file with TMPG DVDauthor (it wants 704x480 or 720x480). TMPG Plus won’t accept the mpg file. I’ve met with limited success with Premiere, but it’s major time consumption.
Nerovision accepts the file nicely, and will convert to DVD format (720x480), or it will export to 720x480 MPEG-2. The problem is that, even though I select Dolby Digital (AC3) audio for the output, I wind up with only PCM (2 channel) out to my external AC3 receiver, even though the same receiver gets Dolby Digital 5.1 when the original MPEG-2 (recorded) file is played.
I’m hoping we might have a few digital audio experts on this forum, and that they might be able to help. (That’s why it’s important to me that I’m posted in the correct category and sub.)
I obviously have the Nero MPEG-2 plugin, and according to Ahead, it includes an AC3 plugin. I’m not sure if I have the correct AC3 plugin. Anyone know what it’s named?