Problem with rotated colliders

I'm making a 2d platformer with the new unity 4.3. I'm using rotated collider2d as platforms.

I want to create an effect like this:

when the player moves up and down the rotated platforms, he will move at the same speed and will always be attached to the collider.

The current situation is: if the player goes up the platform and then stop pressing the key he makes a small annoying jump. and if he goes down he's not attached to the platform.

I tried many things, changing gravity while he's on stairs, changing platform friction, changing the force vector while on stairs, nothing seemed to work like I want.

Any ideas?