package a running VirtualBox environment into a vagrant box and deploy it on aws ec2?

I'm new to vagrant and aws.

I have a vagrant ubuntu image running in my laptop and I want to package it and deploy it into aws. How can I do this?

Here are what I have tried and found:

1. vagrant package --output NAME.box This gave me a ~1GB .box file
2. Found vagrant-aws and vagrant-aws/example_box in github, but it seems to me that it can only deploy a dummy/new box into aws not a existing one? correct me if I was wrong here.
3. Also tried a work-around: I deployed a brand-new ec2 with a amazon machine image (ubuntu) and I upload the NAME.box file into this machine. And I tried to install vagrant and virtual box and manually do the vagrant up. But it told me I can't do it on a xen virtual machine.

Thanks in advance!