Add Light To Shader

Hi guys I wrote a shader which one blend 2 textures :

1. _MainTexture is drawed normaly

2. _SecondTexture is blended to _MainTexture but it is visible when _Mask is on _SecondTexture

Shader work's perfectly but I dont know how to add light to it.

 Properties
    {
           _Color ("Main Color (A=Opacity)", Color) = (1,1,1,1)
          _MainTex ("Base (A=Opacity)", 2D) = ""
          _SecondTexture ("Second Texture (A=Opacity)", 2D) = ""
           _Mask ("Culling Mask", 2D) = "white" {}    
    }
    SubShader
    {
       Pass
       {
          Lighting On
          Blend SrcAlpha OneMinusSrcAlpha

          SetTexture [_Mask] {combine texture * constant ConstantColor[_Color]}

          SetTexture [_SecondTexture] {
          ConstantColor[_Color]
          combine texture * previous
          }

          SetTexture [_MainTex] {
          combine texture  + previous
          }

       }
    }

I trying turn Light On or add tags but when I move any lights to object with this shader then light is not affect on it. I want to achive effect like on standard Diffuse shader