Code:
    <configSections>
        <section name="nhibernate" type="System.Configuration.NameValueSectionHandler, System, Version=1.0.5000.0,Culture=neutral, PublicKeyToken=b77a5c561934e089" />
        <section name="syscache" type="NHibernate.Caches.SysCache.SysCacheSectionHandler,NHibernate.Caches.SysCache" />
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
    </configSections>    
    <nhibernate>
        <add key="hibernate.connection.provider" value="NHibernate.Connection.DriverConnectionProvider" />
        <add key="hibernate.dialect" value="NHibernate.Dialect.MsSql2000Dialect" />
        <add key="hibernate.connection.driver_class" value="NHibernate.Driver.SqlClientDriver" />
        <add key="hibernate.connection.connection_string" value="conn_str" />
        <add key="hibernate.cache.provider_class" value="NHibernate.Caches.SysCache.SysCacheSectionHandler,NHibernate.Caches.SysCache" /> 
        <add key="hibernate.cache.use_query_cache" value="true" />
        <add key="relativeExpiration" value="300" />
    </nhibernate>
    <syscache>        
        <cache region="foo" relativeExpiration="500" priority="4" />
    </syscache>