load a path from a raster based matte

Hi Team

I am trying to articulate the edges of a silhouette of a figure using active light streaks similar to Andrew Kramer's tutorial on audio to animation

http://www.videocopilot.net/tutorials.html?id=64

I am specifically interested in the line electrically passing around the edge of the figure - the body of which will consist of energy fields - an electric man!!

the source for the silhouette is produced in imagineer systems mocha - from which the full body matte can be exported as shape data, as an alpha channel or as a silhouette matte.

I would like to load the edge data as a live path for the light streaks but can't figure a way to do this in AFX,

any help would be very gratefully accepted

Thanks

Paul Richards