Encoding audio for Digital Cinema Packages

This is here to remind me to explore this issue further.  Here's the issue in a nutshell: DCPs expect audio in certain configurations: 2.0, 5.1, 7.1, 9-16 channel.

• 2.0 = Left, Right
• 5.1 = Left, Right, Center, LFE (subwoofer), Left Surround, Right Surround
• 7.1 = Left, Right, Center, LFE (subwoofer), Left Surround, Right Surround, Left Center, Right Center
• 9-16 Channel adds channel 9 through channel 16 to the 7.1 matrix

Notice anything missing?  There's no option for encoding just monaural sound (center channel).  It seems that the best option at the moment is to fake out the audio system by creating and encoding silent audio tracks in the unused channels of a 5.1 matrix for proper center audio sound:

1. Left = silent track
2. Right = silent track
3. Center = monaural audio essence
4. LFE = silent track
5. Left Surround = silent track
6. Right Surround = silent track

I just worry that this is not a proper workaround for the problem of the missing monaural only encoding.  There are some interesting forum threads on this issue that seem to accept that the silent track, while not great, is a viable workaround.

• http://www.film-tech.com/cgi-bin/ubb/f16/t001067/p1.html
• http://dcinemaforum.com/forum/index.php?topic=232.0