Clothing

Hello,
I’ve downloaded this character from blendswap. I took out the rigging so I can use the model as an example for simple rigging in the high school class I teach.

http://www.pasteall.org/blend/31245

I don’t understand how the pants and shirt work, how to apply simple vertex groups to them. When I move the simple rig in pose mode, the shirt stays put.

I’d like the simple rig to control the shirt along with the arm.

Could you help me out with some resources?

Thanks!!

Best,
Robb