How do I change the default sound for the second and subsequent alarms?

Hi 🙂

When I create an event in iCal 4.0.4 I have the option to set multiple alarms, choose the time at which they go off, and what if any sound they make. Right now the default is that an alarm is created to play the Glass sound at the time the first alarm triggers. I believe I may have edited the prefs file at some distant point in the past so that the alarm sound would be Glass by default. Whether or not that is so, I would like the second alarm sound, in fact all of the alarm sounds to default to Glass, but as things stand now the second and subsequent alarm sounds default to Basso. Is there a way for me to change the plist file or something else so that all alarms I set default to the Glass sound file?

Thanks.