Missing DataTriggerBehavior in my Blend 2013

Hi,

Following the PluralSightCours "Extending XAML Applications With Behavior" I now just tried to apply what I learnd.

In the course it was shown how to set radiobuttons via behaviors, using the DataTriggerBehavior. Unfortunately I can't find this behavior in my Blend 2013 -> Assets -> Behaviors:

Am I missing something?

Thanks for help and hints!

Regards
Rainer