Unity and OVRPlayer onParticleTrigger()

I'm trying to get the OVRPlayer hands to interact with a particle system.

I have activated the Trigger and have a script on each of the hands that is attempting to detect OnParticleTrigger or OnParticleCollsion and I'm not getting any messages sent to those scripts.

I can get normal collisions to register with the mesh collider on the hands, but particles dont seem to trigger.

I know the hands are interacting with the particles as I can get the collide and kill interactions to work - but the callbacks never seem to occur.

Am I missing something? Any help would be great!

Cheers,
Rob.