Four channel mix for P2 format?

Question

I'm in the final stages of editing an EPK for an upcoming indie film, but I'm having some problems getting the audio output the way it's supposed to be delivered. The distributor wants the EPK on a master tape with a four channel mix. The problem is getting it to render it out that way.
We shot the EPK on P2 cards (720p), although the finished cut, while predominantly made up of P2 footage, also contains quite a number of production stills, SD footage and clips from the finished film sourced from the final Quicktime render file. Now the producer suddenly decides he wants me to export it as an MXF and put it on a P2 card, which he can then take to his people and have dubbed to HDCAM.
But, even after reading the CS4 manual, which seems to indicate that you can export back to P2 in four channels, I can't get it to work right.
I thought it was because I hadn't set up my sequence timeline for 5.1, so I created a new timeline as a 5.1 output. Then I had trouble porting the clips over to that because of memory issues (big project), so what I decided to do was export the project timeline twice as an MXF sequence. The first time I muted the tracks which had the music and effects on them and exported just the main program. Then I muted the main program audio and unmuted the music and effects and exported again. Then I opened a new project with a sequence that was set up for 5.1. I laid down both exports on the time line, the two video tracks right on top of each other. Then I used Source Channel mappings to route the main program to channels one and two, and the music and effects to channels three and four. I played it on the timeline and saw four channels light up with the mix.
So thinking I had solved the problem, I exported it again as a MXF and examined the output - only to find that the new sequence was only two channels, and only the main program audio. The music and effects were nowhere to be found.
Anybody know how to get this to work? Thanks!

Answer 1

Unfortunately, unless a software CD-4 demodulator exists that can process "modulated" recordings (it might...), you'll need 4-channel hardware capture capability.  This is pretty common for musicians and you might find solutions in the music equipment section of Best Buy.
In terms of software - Audacity is amazing and VERY powerful.  One thing you might be able to do with Audacity is something like:
Record player -> CD-4 decoder -> 4-channel audio capture card/interface -> 4-track WAV file
then
4-track WAV file -> 4.0 or 5.1 channel AC3 (Dolby Digital) audio -> Dolby Digital capable surround receiver
The latter is actually what I do with recordings from my Zoom H2 - however this has 4-channel mic recording but not 4-channel line-in recording.
It looks like, in order to do software CD-4 demodulation, your recording solution will have to have a VERY high samplerate and a much higher cutoff for its lowpass filter than typical for audio - there are likely to be few off-the-shelf solutions for recording the "un-demodulated" CD-4 inputs.  http://en.wikipedia.org/wiki/Quadraphonic_sound#CD-4_.28Compatible_Discrete_4.29_.2F_Quadradisc - In short, I don't think recording to PC and then demodulating is going to be practical.
*disclaimer* I am not now, nor have I ever been, an employee of Best Buy, Geek Squad, nor of any of their affiliate, parent, or subsidiary companies.