Does anyone have any experience with exporting meshes with particle systems from Blender (2.49b)? Is there some trick to it?

I've made a simple mesh with a particle system, but after export when I open it in Nifskope, there's no particle system data at all, just the basic mesh. I know it's been done before but I'm obviously missing something. I've exported as a particle system and I even tried converting the particle system to a mesh, neither work for me.