Create a Soap 11 client in .Net with Custom binding

I am getting error calling a WCF service using a .Net client. I can call the same service using SoapUI. The error is listed below

{"The remote server returned an error: (415) Cannot process the message because the content type 'application/soap+xml; charset=utf-8' was not the expected type 'text/xml; charset=utf-8'.."}

The binding for the service is listed below

         <customBinding>
                <binding name="CustomBinding_IBroker">
                    <security defaultAlgorithmSuite="Basic128" authenticationMode="UserNameOverTransport"
                        requireDerivedKeys="true" securityHeaderLayout="Lax" includeTimestamp="true"
 messageSecurityVersion=

"WSSecurity11WSTrustFebruary2005WSSecureConversationFebruary2005WSSecurityPolicy11BasicSecurityProfile10">
                        <localClientSettings detectReplays="false" />
                        <localServiceSettings detectReplays="false" />
                    </security>
                    <textMessageEncoding />
                    <httpsTransport />
                </binding>
            </customBinding>

Is it possible to indicate on this setting that the intention is to use Soap 11 messaging rather than 12. 

Thanks