Light Trails with slow-mo dancing

Question

Hello all,
I am trying to make some light trails emit from people's hands as they dance.
I am using AE CS5.5 along with Trapcode Particular.
The footage is of a guy hip hop dancing that goes from full speed to super slow speed done in Motion (FCP Suite).  I am just doing the animation someone else is editing it the footage together and doing the slow-motion.
The tutorial I am using (and adapting) is from here: http://ae.tutsplus.com/tutorials/vfx/create-an-illuminating-light-painting-effect/
Here is the link to a example of one of the clips that I am working on (passoword is trapcode): http://vimeo.com/36217419
The problem I am running into is, as you can probably see, 2 things:
1. Whenever the clips goes into super slow-motion, the trail gets really short, especially the second time through.
2. Right before it goes into the super slow-motion, the trail kind of freaks out, gets less "smooth" and goes wherever it wants. 
I have the movement of the hands rotoscoped/keyframed each frame to follow the hand.  I think I may know why the trail gets short, because it's a particle generator and not a actual "tail."  But didn't know how I could do it like this: http://www.youtube.com/watch?v=OC564dRMO1M that clearly goes from full speed to slow motion without any problems.
I have tried putting in keyframes and having the life of the particle go short to longer depending on the speed, but doesn't seem to work.  I also have tried eliminating (and adding) keyframes in the super slow-motion part to see if it would help.  It didn't do anything either way.
I also tried another tutorial found here: http://www.youtube.com/watch?v=RNUGj07DpF8  But it definitely didn't do what I needed it to do.  The light layer (Emitter) wouldn't stay with the null object.
The only idea I have is get the full speed clip, do the light trails, then have them slow it down. 
Any ideas on how to fix both of these problems, so it is a consistent length (even just a longer one) and doesn't "wig out"?  Help me Obi-Wan, you're my only hope.  Thanks in advance.

Answer 1

The only idea I have is get the full speed clip, do the light trails, then have them slow it down. 
Exactly that. You are also misunderstanding how Particular works. Short version: Whenever you keyframe something in Particular, it affects only particles born at that time or later, not existing ones. Therefore changing the life or velocity won't close the gaps. You could only try the Motion Path Feature, but this imposes otehr limitations which also may not resolve your issues...
Mylenium