6 channel AAC conversion

[danvx6]

Hi! Here is my problem: I have an MKV file with an 5.1 channel AAC audio stream, which I have separated with MKVtoolnix. To author a DVD I need the audio to be in AC3 format. After some seraching, I have been unable to find a conversion method that preserves all of the channels. (The only program I found was GoldWave, which output a stereo WAV file that I could convert to AC3 with another program) AAC seems to be a very difficult format to deal with. Any help is greatly appreciated, thanks!

EDIT: I've tried DBpowerAMP with the correct codec, but every time i try to convert (even a test conversion) the program crashes. Has anyone else had this issue?

EDIT 2: I've fixed the previous problem by updating the codec, but now I have to convert a 6-channel WAV file to AC3. I've tried BeLight, but it always outputs 0 KB files! Sony Vegas won't open the file because it has more than 2 channels, and FFMPEGgui work either. For the mercy of others, I will never use the MKV container or AAC audio streams in anything.

[NoFace]

I haven't tried this yet, but it sounds like these people managed to do it.
http://forum.doom9.org/showthread.php?p=666230 . Post back if you try it and it works. I've looked around on the net quite a bit and didn't find a lot of AAC->AC-3 tutorials.