My web.config settings run perfectly fine on IIS7.5. I have tested it on multiple machines.
On IIS 7 it gives the following error:
An error occurred creating the configuration section handler for system.serviceModel/behaviors: Extension element 'dualCertificateClientCredentials' cannot be added to this element. Verify that the extension is registered in the extension collection at system.serviceModel/extensions/behaviorExtensions.
WEB.CONFIG:
<?xml version="1.0"?><configuration><system.web><compilation debug="true" targetFramework="4.0"><assemblies><add assembly="mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/></assemblies></compilation></system.web><system.serviceModel><extensions><behaviorExtensions><add name="dualCertificateClientCredentials" type="DualCertificateClientCredentialsElement,GNACustomBinding,Version=1.0.0.0,Culture=neutral,PublicKeyToken=null" /></behaviorExtensions></extensions><behaviors><endpointBehaviors><behavior name="SecureMessageAndTransportBehavior"><dualCertificateClientCredentials><clientCertificate findValue="XXXXXXXXXXXXXXXXXXXXXXXXXXXXX" storeLocation="LocalMachine" storeName="My" x509FindType="FindBySubjectName" /><transportCertificate findValue="XXXXXXXXXXXXXXXXXXXXXXXXXXXXX" storeLocation="LocalMachine" storeName="My" x509FindType="FindBySubjectName" /></dualCertificateClientCredentials></behavior></endpointBehaviors></behaviors><bindings><customBinding><binding name="SecureMessageAndTransportBinding"><security messageSecurityVersion="XXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
authenticationMode="MutualCertificate"/><httpsTransport requireClientCertificate="true"
authenticationScheme="Negotiate"
useDefaultWebProxy="true"
manualAddressing="false"/></binding></customBinding></bindings><client><endpoint address="XXXXXXXXXXXXXXXXXXXXXXXXXXXXX" binding="customBinding" bindingConfiguration="SecureMessageAndTransportBinding"
behaviorConfiguration="SecureMessageAndTransportBehavior" contract="XXXXXXXXXXXXXXXXXXXXXXXXXXXXX" name="PartnerApplicationServicePort"/></client></system.serviceModel></configuration>