System Sounds

From the command-line
luna-send -n 1 palm://com.palm.audio/systemsounds/playFeedback '{"name":"shutter"}'

Inside a mojo app
this.controller.serviceRequest('palm://com.palm.audio/systemsounds', {   method:"playFeedback",   parameters:{ name: 'shutter' } });

Where shutter equals the file name, minus the extension, of a file found below.

List of default sounds
root@castle:/# ls /usr/share/systemsounds/

alert_buzz.pcm              dtmf_0.pcm                   error_02.pcm                 shuffle_05.pcm appclose.pcm                dtmf_1.pcm                   error_03.pcm                 shuffle_06.pcm back_01.pcm                 dtmf_2.pcm                   focusing.pcm                 shuffle_07.pcm browser_01.pcm              dtmf_3.pcm                   launch_01.pcm                shuffle_08.pcm card_01.pcm                 dtmf_4.pcm                   launch_02.pcm                shuffling_01.pcm card_02.pcm                 dtmf_5.pcm                   launch_03.pcm                shutter.pcm card_03.pcm                 dtmf_6.pcm                   notification_buzz.pcm        switchingapps_01.pcm card_04.pcm                 dtmf_7.pcm                   pagebacwards.pcm             switchingapps_02.pcm card_05.pcm                 dtmf_8.pcm                   pageforward_01.pcm           switchingapps_03.pcm default_425hz.pcm           dtmf_9.pcm                   ringtone_buzz.pcm            tones_3beeps_otasp_done.pcm delete_01.pcm               dtmf_asterisk.pcm            shuffle_02.pcm               unassigned.pcm discardingapp_01.pcm        dtmf_pound.pcm               shuffle_03.pcm               up2.pcm down2.pcm                   error_01.pcm                 shuffle_04.pcm

Notes:

 * Replacing or placing new file in this directory requires a restart of pulseaudio:

root@castle:/# initctl stop pulseaudio; initctl start pulseaudio


 * Pulseaudio seems to favor the .pcm extention if there are similarly named files. For example, shutter.pcm vs shutter.wav.
 * Compatible file types: .pcm, .wav
 * Incompatible file types: .mp3