I wasn't sure if it was best to bump this old thread or start a new one asking a very similar question...I decided to bump.
I have picked up Adobe After Effects since this post and again I'm doing work with doubles and clip cutting but unfortunately I cannot find the tool you are mentioning, David. The silhouette roto tool (unless it's a plug-in or something) doesn't seem to be in After Effects CS3. Is there another tool that can work...I tried all the matte options, however, I could not seem to get them to do any cutting in half or anything like that.
Intel Core 2 CPU 6600 @ 2.40 GHz
2 GB RAM
Nvidia GeForce 7600 GS