Having issues adding Custom Behavior to a WCF service web.config file

I am trying to add a custom behavior to the web.config of a wcf
service. I have created the custom Behavior and the Behavior Section
classes and added the following code to the Web.config of the service.
When I tested out the service, looks like the custom behavior was not
getting applied. If possible please let me know what needs to be done
for the custom behavior to start working for the client too. Any help
is greatly appreciated. Given below is the contents of the web.config
file. Thanks!!

<?xml version="1.0"?>
<configuration
xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
<system.serviceModel>
<services>
<service name="Core.Services.PatientService"
behaviorConfiguration="SecurityTokenValidatorBehavior">
<endpoint
contract="Core.Services.IPatientService"
binding="wsHttpBinding"/>
</service>
</services>
<behaviors>
<behavior
name="SecurityTokenValidatorBehavior"
returnUnknownExceptionsAsFaults="true">
<SecurityTokenValidatorBehaviorSection />
</behavior>
</behaviors>
<extensions>
<behaviorExtensions>
<add
name="SecurityTokenValidatorBehaviorSection"
type="Core.Services.ServiceExtensions.SecurityTokenValidatorBehaviorSection*,Core.Services.ServiceExtensions,

Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"/>
</behaviorExtensions>
</extensions>
</system.serviceModel>
</configuration>