I have a simple JSF 2.0 composite component example.
You need to reference composite component attribute values by #{cc.attrs.<name>} where <name> is the attribute name. So, this should do:
<h:inputText value="#{cc.attrs.model.vorname}">
Unrelated to the concrete problem, all that <html><head><body> in the composite is unnecessary. I suggest to use <ui:component> since that's more clear. See also our composite component wiki page for examples.