How to create a sdcard in AVD?

I use emulator to work. In this chapter, I need AVD to be equiped with a SD Card so that I can use the camera to take photo. When I try to create a AVD with a SD Card, I found that the AVD doesn’t support sdcard option. So I want to know why and how to fit it? Thank you.

PS: I have successfully create a image file for sdcard to store information which named sdcard.img, using the cmd instruction under the directory of Sdk\tools. So the problem doesn’t located in this. And I have tried two different ways to bind sdcard with AVD. One is to choose the sdcard path for AVD in the AVD-creation window, another is to use cmd instruction to bind the sdk to AVD with the feedback result shows that “emulated hardware doesn’t support SD Cards. -sdcard option ignored”.

Here are the screenshots related with the problem: