How to create Trail Renderer with an outline

Hello. I was wondering how I would make a trail renderer with an outline? Basically this is a trail that has an outline, and the inside of the trail is a different color, like black. I have tried using the Silhouette-Outlined Diffuse shader
http://wiki.unity3d.com/index.php?title=Silhouette-Outlined_Diffuse
But it just messed with it.

Just create a texture in paint or photoshop like a white background with two horizontal black lines (up and down) put it into a material and then put that material in the trail renderer component