Strok/Outline around TextMesh using Shader?

Im trying to find a way to add a stroke/outline around my TextMesh, using a shader or something. Im already using another shader, and wanted to combine it. but with no way of knowing how to. The shader i use at the moment is this:

 Shader "GUI/3D Text Shader" { 
     Properties {
         _MainTex ("Font Texture", 2D) = "white" {}
         _Color ("Text Color", Color) = (1,1,1,1)
     }
     SubShader {
         Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
         Lighting Off Cull Off ZWrite Off Fog { Mode Off }
         Blend SrcAlpha OneMinusSrcAlpha
         Pass {
             Color [_Color]
             SetTexture [_MainTex] {
                 combine primary, texture * primary
             }
         }
     }
 }

It does so i can't see the TextMesh through the walls. Anyone knows how to add it?