General :: Two Versions Of One App Installed At Same Time?

I want to know how to install two versions of one same application at the same time.

As a matter of fact, I want to install Opera Mini 4.2 China Version and Opera Mini 4.2 Internaional Version at the time. But...Since Opera Mini 5 makes it difficult to describe the question, here takes HelloWorld.apk as an example.

Well, there are two versions of the application "HelloWorld": 1.0 and 1.1. (This is just an example)

I have installed HelloWorld 1.0 on my phone, and when I try to install HelloWorld 1.1, the 1.0 version will be replaced. But...I want to have both of them installed on my phone. That is to say, there will be two "HelloWorld" icons in the app drawer.

I use APKTool to extract the com.hello.world.apk into some "text" files, including an AndroidManifest.xml and a lot of *.smali files. In the AndroidManifest.xml, I saw this:

<manifest package="com.hello.world" versionCode="100" versionName="1.0">

I changed the value "com.hello.world" to "com.goodbye.world". Then I re-build the apk file and transferred it to my phone.

I installed the modified package, it was successfully installed and I see two "HelloWorld" icons in my app drawer!

I try to launch the HelloWorld 1.0, it succeeds.
I try to launch the HelloWorld 1.1, it FCs immediately.

Well, this is my situation. How can I make both of them launch-able in my phone? Is it possible? What should I modify apart from "package" filed in AndroidManifest.xml?