Particle System - new Modul Triggers - How to use

Hello,

i will test the new Modul Triggers in the Particle System (in Beta 5.4). But what Code do i need?
I have test with OnParticleTrigger, but nothing happens.

Code (CSharp):

1. void OnParticleTrigger (){
2. Debug.Log ("Trigger");
3. }

Its a 2D-Game.
The Code are inside some Sprites and there are arround of a Particle System.
The Sprites have 2d Collider.

I have use in the Trigger Modul:
- all Sprites inside
- Enter --> Callback
- all other --> Ignore (have test Callback on all, too, but nothing happens)
- Radius scale are biggest enough
- Visualize Bounds On to see Radius

For more information what should happen look at this Thread:
http://forum.unity3d.com/threads/particle-collision-only-trigger.385437/

Whats the right code to become a trigger with the ParticleSystemOverlapAction.Callback
http://docs.unity3d.com/540/Documentation/ScriptReference/ParticleSystemOverlapAction.html

And there is no Triggers-documentation in the new 5.4 beta documentation under "Particle System Modules".
http://docs.unity3d.com/540/Documentation/Manual/

thanks