Hi,
I can't find a decent source of information about flac's --channel-map option
that will encode a wav file (that plays back perfectly in foobar 2000) with 5 channels that are ordered as: Lf-Rf-LFE-Ls-Rs

Flac will encode them by default as Lf-Rf-C-Ls-Rs...
What do I need to do to get flac to "understand" the correct channel map.

I finally gave up on convincing flac to accept arbitrary channel mapping.

I just used Audacity to add an additional center channel, which was obviously empty, and encode it.