How to use SIM card in Droid 2 Global?

Question

So I have a Droid 2 Global because it has SIM card capabilities. I called Verizon to allow international roaming. Then I got the unlock code for my phone. Next I put a new-bought SIM card from China Mobile into my Verizon Droid 2 Global.
However, when someone calls my China Mobile phone number, my phone does not react. The caller hears a prerecorded message that the China Mobile phone number is incorrect or not connected.
When I call with my Droid 2 Global with the China Mobile SIM card inside, the receiving person sees my Verizon phone number.
My question is: How do I get my Droid 2 Global to recognize and use my China Mobile SIM card?
I don't want it to use my Verizon phone number while I am overseas. I like my Verizon service in the U.S., and I plan to return to it.  I just thought the idea of a global phone with a SIM card was to be able to travel to other countries and use another SIM card if need be, and the sales representatives at my local Verizon store sold me this idea of international usage. Other users seem to have no problem. Please inform me of how it works
Thank you!

Answer 1

Hi mortb, thanks for your input.
However, that is not true about SIM cards. You can find accurate information about SIM cards through your search engine or even Wikipedia. SIM cards are meant to be swapped out. SIM cards are used in Europe and Asia more than the U.S. "The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device" (Wikipedia- SIM cards).
A SIM card holds the prepaid account value, telephone number, the user's address book, call logs, texts, etc. A lot of websites give the analogy: Say your phone is dead but you need to make a call. You can use your friend's cell phone with your SIM card and call. You won't be using your friend's minutes, but your own because you are using the minutes from your SIM card.
In my case, I want to use a local cell phone provider to make local calls. Theoretically speaking, I can do so if I swap out my SIM card for a local network's SIM.
Now Verizon locks all its phones to their Verizon SIM cards, so Verizon phones can only use Verizon SIM cards, but the Droid 2 Global allows you to unlock your SIM, meaning that you are going to put in another SIM card, aka another cell phone service provider.
So I am confused why I cannot use another carrier's SIM card. Can anyone explain why? Or what can I do to sync my China Mobile SIM to my Droid 2 Global?
Also referenced: http://community.vzw.com/t5/DROID-2-by-Motorola/Unlocking-Droid-2-Global/td-p/365596