USB Camera to Android

Hi there! I got a problem connecting my USB Camera to my tablet(ASUS K10A) The device reads only the front and back camera I'm searching for answers but still no luck, I need help. Thanks in advance!

I put this line in my AndroidManifest to use an external camera device if one is connected.

   <uses-permission android:name="android.permission.CAMERA" />
   <uses-feature android:name="android.hardware.camera.external" android:required="true"/>

My working code:

   #pragma strict
     private var devices : WebCamDevice[];
     public var deviceName : String;
     private var wct : WebCamTexture;
     private var resultString : String;
      
      
     function Start() {
         yield Application.RequestUserAuthorization (UserAuthorization.WebCam);
      
         if (Application.HasUserAuthorization(UserAuthorization.WebCam)) {
            devices = WebCamTexture.devices;
            deviceName = devices[0].name;
            wct = new WebCamTexture(deviceName, 640, 480, 30);
            renderer.material.mainTexture = wct;
            wct.Play();
            resultString = "no problems";
         } else {
            resultString = "no permission!";
         }
     }
      
     function OnGUI() {
         for (var i = 0; i < devices.length; i++) {
            GUI.Box(Rect(100, 100+(i*25), 300, 25),devices[i].name);
         }
         GUI.Box(Rect(100, 100+(i*25), 400, 25),resultString);
     }