Connecting SAP system from C# application via .NET Connector 3.0

You can try using below code:

<SAP.Middleware.Connector>
    <ClientSettings>
      <DestinationConfiguration>
        <destinations>        
          <add NAME="Name" USER="User" PASSWD="orly" CLIENT="100" LANG="EN"
                ASHOST="host.domain.com" SYSNR="70" MAX_POOL_SIZE="10" IDLE_TIMEOUT="20"
                SNC_PARTNERNAME="p:CN=mycn.com, OU=A, O=B, L=C, C=GB"
                SNC_MYNAME="p:CN=myname.com, C=GB, O=A, OU=B"
                SNC_QOP="8" SNC_MODE="8" TRACE="2"/>        
        </destinations>
      </DestinationConfiguration>
    </ClientSettings>
</SAP.Middleware.Connector>