I record my audio in GarageBand and export a aiff audio file.
Then I open the *.aiff audio file with Audacity, select and export the region I need as:
WAV (Microsoft) signed 16 but PCM
There is a "Options" button but for the selected format, no options are available.
The weird thing is that at the beginning, it all worked without a hitch.
Anyway, I re-use most of my sound samples and by now have all the extensions I need.
Eventually, i will examine the .aiff file with GarageBand spits out and see if a different export format will work as expected.
Thanks for clearing that up.
Btw: I LOVE C2! If it wasn't for C2, I'd still be making Flash apps which is a dead end solution.