Here's additional info I also posted in the "Using Custom Effects in SF2" thread in Knowledge Base:
Small note regarding shaders types.
if you want to upgrade particular "custom" effect to SF2 standard, and are not sure which shader should apply to what material, here's simple rule I use:
-for the "volumeric" emitters like smoke, groundmist, dust, dirt or debris types of particles use the EffectShaderName=effectLightLevel.fx
(generally, materials that have BlendOp=BLEND_SRC_ALPHA particle blending option)
-for the fire, explosion, light, flash, flare, streak and so on use EffectShaderName=twColor1.fx
(materials that have BlendOp=BLEND_INV_SRC_ALPHA_ADD_SRC)
I know this doesn't cover all the possible materials types, the most common, but should point one in the right direction