I think this is one of those paintFX that just don't translate well after converting to polygons. Even if you set a high poly limit on the conversion settings, you still end up with a mash up of tiny triangular pieces which just look like little splinters. You can:

1. Use a particle system and do the glow in post. More versatile.
2. Software render out the image using render layers with an override to use maya software renderer, assign a "use background" to the objects you'd like to "cut out"(because they'll be rendered in mental ray). Then composite the images.