I'm trying to conserve processor power by recording in native file format, PCMU in my case. It works great with the following line

session:execute("record", "/tmp/my_recording."..session:getVariable("read_codec"));

however it fails to work with

session:execute("record_session", "/tmp/my_recording."..session:getVariable("read_codec"));
or 
record = api:execute("sched_api", '+1 none uuid_record '..session:getVariable("uuid")..' start /tmp/my_recording.'..session:getVariable("read_codec"));

Why is it that it works with record, but not with record_session or uuid_record? Is there something I'm over looking? In the latter two the consul reports

2009-11-22 18:39:04.265284 [INFO] mod_native_file.c:82 Opening File [/tmp/my_recording.PCMU] 8000hz

as if it's recording, but /tmp/my_recording.PCMU never shows up. However if I change it to .wav instead of .PCMU it works. Any ideas?

--matt