Yup, if I had had Poser or had taken the time to do something against a greenscreen, i would have had motion in my tutorial, but glad you were able to use it. What you could do is lower the number of particles, or like you said, place the original poser clip in the background so that parts of it can been seen through the fire. I noticed on my burning flash clip, that I could still see a great deal of the figure underneath the fire (feet, arms, hands, and occasionally the chest).
Cheers!
Stephen Schleicher
schleicher@mindspring.com
http://www.mindspring.com/~schleicher