The best way to learn using CocoStudio is to have a look at the C++ samples inside cocos2d-x 2.2.
The new UI Classes don’t even require CocoStudio, and can be used as a replacement for CCControlExtension, or even mix them up.
The only problem I found is some stability issues with GameDataEditor, which sometime crashes trying to load some XLS or CVS, but overall GREAT work. The UI and scene editor are pretty stable and overall fantastic, keeping in mind that this project just born.
Thanks, and hope this projects goes on!