Stairs and collision

I'm trying to set up an invisible ramp under my stairs that handles the collision, i'm using the 3rd option for collision but my man is still sliding down the ramp as I try to progress, stopping altogether even. I have basic gravity (Y=Y+yvel where y_vel changes from jumping and falling) Any ideas as to what I might be doing to undermine my own progress? Thanks guys!

Oh, and I'm using .x models.