Shadows don't appear through a custom shader

Hi

I am working on a project to simulate the hololens in VR, and I use custom shaders, which allow me to have holograms that I can only see through the Hololense. This works well but I have a little problem : I can't see the shadows of the objects in my scene through the Hololense, and I don't understand why.

Can someone help ?

Thanks a lot

here are the codes of the hololens shader and a hologram shader

 Shader "Custom/shader_HoloLens" {
     Properties {
         _Color ("Color", Color) = (1,1,1,1)
         _MainTex ("Albedo (RGB)", 2D) = "white" {}
         _Glossiness ("Smoothness", Range(0,1)) = 0.5
         _Metallic ("Metallic", Range(0,1)) = 0.0
     }
     SubShader {
         Tags {"Queue"="Geometry" "RenderType"="Tansparent"}
         LOD 200
         ZWrite On
         Stencil
         {
             Ref 1
             Comp Always
             Pass Replace 
         }
         CGPROGRAM
         // Physically based Standard lighting model, and enable shadows on all light types
         #pragma surface surf Standard  addshadow alpha 
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _MainTex;
 
         struct Input {
             float2 uv_MainTex;
         };
 
         half _Glossiness;
         half _Metallic;
         fixed4 _Color;
 
         // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
         // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
         // #pragma instancing_options assumeuniformscaling
         UNITY_INSTANCING_CBUFFER_START(Props)
             // put more per-instance properties here
         UNITY_INSTANCING_CBUFFER_END
 
         void surf (Input IN, inout SurfaceOutputStandard o) {
             // Albedo comes from a texture tinted by color
             fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
             o.Albedo = c.rgb;
             // Metallic and smoothness come from slider variables
             o.Metallic = _Metallic;
             o.Smoothness = _Glossiness;
             o.Alpha = 0;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }

 Shader "Custom/shader_Hologram" 
 {
     Properties 
     {
         _Color ("Color", Color) = (1,1,1,1)
     }
     SubShader 
     {
         Tags { "Queue"= "Transparent" "RenderType"="Transparent" }
         LOD 200
         Stencil
         {
             Ref 1
             Comp equal
         }
 
         CGPROGRAM
         #pragma surface surf Lambert alpha:blend
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _MainTex;
         float _BLABLA;
 
         struct Input 
         {
             float2 uv_MainTex;
             float3 worldPos;
         };
 
         fixed4 _Color;
 
         void surf (Input IN, inout SurfaceOutput o) 
         {
             fixed4 c = _Color;
             float3 localPos = IN.worldPos;
             float dist = length(_WorldSpaceCameraPos - localPos);
 
             o.Albedo = c.rgb;
             o.Alpha = - pow((0.4 * dist - 1.3), 2) + 0.8;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }