Projector affected by light and shadows(car vinyls, blood spatter or bullet holes)

I'm trying to project a decal onto a car that is affected by light and shadows.

I've messed around with this for many days now, here's what I have:

     Shader "VinylShader"
   {
   Properties {
         _Color ("Main Color", Color) = (1,1,1,1)       
      _ShadowTex ("Cookie", 2D) = "" { TexGen ObjectLinear }
      _FalloffTex ("FallOff", 2D) = "" { TexGen ObjectLinear }
   }


   Subshader {
   
     
      
    
      Pass {
         ZWrite off
         AlphaTest Greater 0
         Offset -1, -1
         //Fog { Color (0, 0, 0) }
         Color [_Color]
         ColorMask RGB
         
         
             Material {
                 Diffuse [_Color]
                 Ambient [_Color]
             }
             
             Lighting On
             SeparateSpecular On
          Blend SrcAlpha OneMinusSrcAlpha   
         //Blend DstColor One
         SetTexture [_ShadowTex] { combine texture* primary // primary, ONE - texture
            Matrix [_Projector]
         }
         SetTexture [_FalloffTex] {
            constantColor (0,0,0,0)
            combine previous lerp (texture) constant
            Matrix [_ProjectorClip]
         }
         
      }
      
   }
   
 }