I search for solutions in this order: Past Code, Unreal Source, Wiki, BUF, groups.yahoo, google, screaming at monitor. – RegularX

From Unreal Wiki, The Unreal Engine Documentation Site

VolumeTriggers catch trigger events and delegate them to Volumes, especially PhysicsVolumes. This is neccessary, because by default Volumes are static actors and thus can't be triggered regularly.

[edit] Related Properties (Inherited From Actor)

[edit] Events Group

name Event 

Match this property with the Events -> Tag of the Volume to be triggered.

name Tag 

Match this property with the event name the VolumeTrigger should "listen" for.