AppDomain domain = AppDomain.CreateDomain("NewDomain");
var xxx =
                    (xxx)domain.CreateInstanceAndUnwrap(
                    System.Reflection.Assembly.GetCallingAssembly().FullName,//System.Reflection.Assembly.GetExecutingAssembly().FullName,
                    "xxx",
                    false,
                    System.Reflection.BindingFlags.CreateInstance,
                    null,
                    null,
                    null,
                    null);

xxx.RunService();

<?xml version="1.0"?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
    <system.serviceModel>
...
        <client>
            <endpoint address="https://myServer/SoapBuffered"
                binding="customBinding" bindingConfiguration="CustomBinding_myServer"
                contract="FZCore.FZCoreServiceContract" name="CustomBinding_myServer">
                <identity>
                    <userPrincipalName value="xxx@company.lan" />
                </identity>
            </endpoint>
        </client>
    </system.serviceModel>
</configuration>