the hardware render buffer is used to hardware render particles (doh! ) and thus i'm not sure if GI joe will affect the particles. As a general rule hardware rendered particles suck cause they are rendered in open gl and thus look crappy (technical explanation i know!! )
If you want to use the GI_Joe script i think you're gonna have to use software rendered particles (indicated by the "s/w" after the particle type in the type options)
hope this is helpfull
Alan
Technical Director - Framestore
Currently working on: Your Highness
IMDB