2D Collider ?

Hi guys I have a 2D maze.png with gama and I want to make 2D collider.

Polygonal Collider is cca good but I dont know how to add or delete paths so the collider is wrong.

Edge Collider is just a line with 2 vertecies.

Any ideas how to do it?alt text

unity 4.6

Hold Shift and click anywhere on the green colider line and drag it. it will create a new pivot point.