how to make virtual buttons created visible?

I have encountered a problem while creating virtual buttons using Unity for an Android Augmented Reality application. My buttons cannot be seen through the phone camera though they can function well. I have imported my own image trackables and have placed buttons above the image trackable plane. Could anyone suggest what goes wrong? I have tried different shaders, but buttons are still invisible. Thanks for your help.

Virtual Buttons will not show on a device.
An alternative is to add a Cube or Plane to it, so that you know where it is. You can also use an Empty GameObject with a Halo functionality to give you some sort of indication.

Hope this helps.

can you give me script virtual button?

do anyone have a script for , on virtual button click , the canvas appears and a text displays