I'm using the Adobe Premiere version from Kelly Industries because I had problem with the standard one.
In this version you can choose the sequence of the channels by clicking in the bottom left corner (L R Ls Rs C LFE or L R C LFE Ls Rs).
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In my sound card LFE is channel 6, but with a 5.1 setup.
In any case it should not be difficult to identify the LFE with some trials.