Belt drive

[skatun]

I am try to figure out how to use the belt mechanism. I have created a belt mechanism with 4 pulleys where 1 is driven by a servo motor. From the belt curve i created a solid part by using extrude. At a given distance from one end of the belt curve i modeled a small bump in the belt.

The problem is that this bump does not move..

How can i get it to move? I want my belt to move another part attached to belt.

Thanks