Can't see particles through a transparent caustic object...

My problem is with this image I’m currently working on:

The main sphere is a raytraced-transparent uvsphere with 5xcaustics, and I’ve made an explosion using particles which renders fine outside of the sphere, but as soon as I put it inside it just disappears. Any help? I’ve tried quite a few things, such as unified render which didn’t make a difference.

I don’t think raytracing supports particles.

more specifically, raytracing does not support halos.

Ah thank you. How annoying. Is there any alternative to using halo’s, which would achieve similar effects? If the particles system still works I’d like to use that.

you could use dupliverts/frames(can’t remember which) but texturing will be more difficult.

You could probably use a circle with increasing alpha toward the edges and apply it to planes. I never used it but they’re not halos or particles.