I did some research, and there is no way to turn the AF beep off conventionally on the SD1100 (from the menus). I tried get_prop/set_prop to change the audio channel, but that didn't do anything.
Audio channels (0=1ch, 1=2ch). Right channel mute if 2ch selected.
get_prop returned 0 even when I toggled the mute from the menus, and other than that I couldn't find any other mention of a way to mute the camera from a script. I guess I will resign myself to not having any beeps in my script, as they weren't entirely necessary in the first place. Thanks for your help reyalp!
Edit:
As for my mission
, the Ixus 80/SD1100 doesn't let me play any sounds in mute except for sound #7. In mute, sound #7 could not be turned off (on my camera). When unmuted, sound #7 works as it should, and I expect the other 7 sounds do as well.
