How to add an alpha channel to Unity Toon shader?

Hi,

I was wondering how this might be done?

Thanks.

The code for the Toon shader is as follows (Basic Outline unlit version):

 Shader "Toon/Basic Outline" {
  Properties {
  _Color ("Main Color", Color) = (.5,.5,.5,1)
  _OutlineColor ("Outline Color", Color) = (0,0,0,1)
  _Outline ("Outline width", Range (.002, 0.03)) = .005
  _MainTex ("Base (RGB)", 2D) = "white" { }
  _ToonShade ("ToonShader Cubemap(RGB)", CUBE) = "" { Texgen CubeNormal }
  }
  
  CGINCLUDE
  #include "UnityCG.cginc"
  
  struct appdata {
  float4 vertex : POSITION;
  float3 normal : NORMAL;
  };
 
  struct v2f {
  float4 pos : POSITION;
  float4 color : COLOR;
  };
  
  uniform float _Outline;
  uniform float4 _OutlineColor;
  
  v2f vert(appdata v) {
  v2f o;
  o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
 
  float3 norm   = mul ((float3x3)UNITY_MATRIX_IT_MV, v.normal);
  float2 offset = TransformViewToProjection(norm.xy);
 
  o.pos.xy += offset * o.pos.z * _Outline;
  o.color = _OutlineColor;
  return o;
  }
  ENDCG
 
  SubShader {
  Tags { "RenderType"="Opaque" }
  UsePass "Toon/Basic/BASE"
  Pass {
  Name "OUTLINE"
  Tags { "LightMode" = "Always" }
  Cull Front
  ZWrite On
  ColorMask RGB
  Blend SrcAlpha OneMinusSrcAlpha
 
  CGPROGRAM
  #pragma vertex vert
  #pragma fragment frag
  half4 frag(v2f i) :COLOR { return i.color; }
  ENDCG
  }
  }
  
  SubShader {
  Tags { "RenderType"="Opaque" }
  UsePass "Toon/Basic/BASE"
  Pass {
  Name "OUTLINE"
  Tags { "LightMode" = "Always" }
  Cull Front
  ZWrite On
  ColorMask RGB
  Blend SrcAlpha OneMinusSrcAlpha
 
  CGPROGRAM
  #pragma vertex vert
  #pragma exclude_renderers shaderonly
  ENDCG
  SetTexture [_MainTex] { combine primary }
  }
  }
  
  Fallback "Toon/Basic"
 }