[ecasound] how to upmix mono audio to stereo?

I have a need to take an audio file of variable format and channels and
turn it into an AAC file with 16 bit, 44100 stereo.
However, when I give the command line below it is producing only sound
in the left channel. Some but not all of the input files are in fact
mono channel. It appears that ecasound is mixing everything down
instead of up... lowest common denominator?
I am doing something wrong but even with googling I am not finding what
I need for this to work.
Details:
OSX 10.5
ecasound 2.6.0

command line:
/opt/local/bin/ecasound -a:0 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,3.0,select,0,2.37714,/Users/jayson/testbed/timelines/HVARun/9cbd35cc-04e8-43a4-b719-ce35dc8ca923.wav
-a:1 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,5.57714,select,0,0.901224,/Users/jayson/testbed/timelines/HVARun/71a474b4-9de4-4e29-806c-3dc056d16fcb.wav
-a:2 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,6.478364,select,0,0.973787,/Users/jayson/testbed/timelines/HVARun/81159bc5-d6af-4b45-86a9-0d9099fd8ea9.wav
-a:3 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,7.452151,select,0,1.66531,/Users/jayson/testbed/timelines/HVARun/20471550-a453-45f9-acdf-395885954e30.wav
-a:4 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,9.217461,select,0,4.13113,/Users/jayson/testbed/timelines/HVARun/a6e6065e-49d9-45ed-9189-a3b09f3451ad.wav
-a:5 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,13.448591,select,0,5.26512,/Users/jayson/testbed/timelines/HVARun/dc8f743b-fe43-4931-a51a-caa1c5f44c34.wav
-a:6 -f:s16_le,2,44100,interleaved
-i:resample,auto,playat,18.813711,select,0,3.12308,/Users/jayson/testbed/timelines/HVARun/2cf71f75-4d64-46a1-80fd-f4657903b6a0.wav
-a:0,1,2,3,4,5,6 -o /Users/jayson/tmp/manual.aac

Output:
********************************************************************************
* ecasound v2.6.0 (C) 1997-2009 Kai Vehmanen and others
********************************************************************************
[* Session created *]
[* Chainsetup created (cmdline) *]
[* Connecting chainsetup *]
(eca-chainsetup) 'nonrt' buffering mode selected.
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_le,1,44100
for object 'resample:playat (tried to open with -f:s16_le,2,44100).
(eca-chainsetup) Opening input "resample:playat", mode "read". Format:
s16_le, channels 1, srate 44100, interleaved (locked params).
(eca-chainsetup) NOTE: using existing audio parameters -f:s16_be,2,44100
for object '/Users/jayson/tmp/manual.aac (tried to open with
-f:s16_le,2,44100).
(eca-chainsetup) Opening output "/Users/jayson/tmp/manual.aac", mode
"write". Format: s16_be, channels 2, srate 44100, interleaved (locked
params).
[* Chainsetup connected *]
(eca-control-objects) Connected chainsetup: "command-line-setup".
[* Controller/Starting batch processing *]
[* Engine - Driver start *]

[* Engine - Processing finished *]
[* Controller/Batch processing finished (0) *]
(eca-control-objects) Disconnecting chainsetup: "command-line-setup".
[* Chainsetup disconnected *]

Thank you for your help.

-- 
Jason Galyon
Silver Screen Tele-Reality, Inc. 
http://www.sister.tv | http://www.videocarlot.tv
Phone: 972-855-3500 |  Fax: 413-778-2146
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