ClaimsAuthenticationManager dont get executed

Hi,
i tried to build a WebApplication (.net 4.5) that uses Claims (just like the example from Microsoft at : http://msdn.microsoft.com/en-us/library/hh291068 ).
Regular Forms Authentication works like expected and i can verify that an ClaimsIdentity is generated. But the Claims Tranmsformation never get called. I did all the Steps from the Example: added claimsAuthenticationManager to web.config; Created a Subclass of ClaimsAuthenticationManager and so on. But, as i said, the Transformation never happens.
Any Idea why my ClaimsAuthenticationManager never gets called?
 
Thanks for your help,
 
Matthias
 
 
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