Error by registering of custom behavior

During development of custom behavior you may get following error:

Extension element 'myEndpointBehaviorExtension' cannot be added to this element. Verify that the extension is registered in the extension collection at system.serviceModel/extensions/behaviorExtensions.

Parameter name: element

To register the custom behavior the behavior extension which is of type BehaviorExtensionElement. Following configuration snippet has to be used:

<extensions>

<behaviorExtensions>

<add name="myEndpointBehavior" type=" MyNamespace.MyEndpointBehaviorExtension, MyLibrary, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />

</behaviorExtensions>

</extensions>

Additionally, the real behavior, which is in following example of type IEndpointBehavior, should be registerd as shown below:

<endpointBehaviors>

<behavior name="some name">

<myEndpointBehavior />

</behavior>

</endpointBehaviors>

</behaviors>

However, if the extension section contains following configuration the configuration system will throw named exception:

<extensions>

<behaviorExtensions>

<add name="myEndpointBehavior" type="MyNamespace.MyEndpointBehaviorExtension, MyLibrary" />

</behaviorExtensions>

</extensions>

Be sure that the version of the assembly, culture and the public key are specified. Otherwise the initialization will fail.