Solved Problem with ConfigurationSerialization

Hello guys,
I have a class which implements ConfigurationSerializable. It has an attribute which also is ConfigurationSeriable. If I save the first object into an yaml config it looks fine. But if I load it again the second object is null. I am pretty shure that I registred the class right.
What am I doing wrong?
EDIT: A little example http://pastebin.com/DS25MXyy

Sloved by myself

EDIT by Moderator: merged posts, please use the edit button instead of double posting.