3D Text Shade do not work properly (Characters occluding other characters)

Greetings,

I have a 3D Text Shader, which make 3D text to not be rendered through walls and object.

Here is the Shader

 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 On Fog { Mode Off } 
    Blend SrcAlpha OneMinusSrcAlpha 
    Pass { 
       Color [_Color] 
       SetTexture [_MainTex] { 
          combine primary, texture * primary 
       } 
    } 
 } 
 }

When I rotate my text, it does not render correctly. Parts disappear, sometime whole letters. As seen here : http://img832.imageshack.us/img832/707/bug3dtext.png

Any ideas what might happen? I used this shader in an old version of unity 3D (3.0) and it worked perfectly. Even now, If I open that old project. It still works perfectly.

Edit: I've found the bug, some fonts are non-standard and characters overlaps. This cause and occluding/rendering error.

So to rectify this, I'd need some way that characters does not occlude letter parts of the same mesh.