Vision event for alarm unshelve

There is an extension function for onShelve for the alarm status table, but I don't see anything to catch the unshelve in this table or in general. Is there a native method that I can catch when an alarm is unshelved, either by user or automatically when it expires, or do I need to roll my own method?

I just added to my Alarm Summary UDT resource to capture when an alarm is acknowledged, shelved, and unshelved. I couldn't find any native event that could determine unshelved and since Perspective doesn't have any extension functions for now this is the better solution since it's common between Vision and Perspective.