xaml --- app.config need upgraded?

Think I will get started Silverlight real soon. Now, with ASP.NET/app.config we can have:

Code:

---

<configuration>
...

    <log4net configSource="Config\log4net.config" />
   
    <MyCustomSection>
          <UtilSettings configSource="Config\UtilSettings.config" />
    </MyCustomSection>

    <appSettings>
       
    </appSettings>
...
</configuration>

---

Can we do something similar in app.xaml? Also what about log4net and nhibernate? I suppose they can't be supported in app.xaml yet? Or am I wrong about that? Can you just put this in app.xaml and expects things still works without code change?

Code:

---

<?xml version="1.0" encoding="utf-8" ?>
<log4net debug="false">
  <appender name="XmlSchemaFileAppender" type="log4net.Appender.FileAppender">
        <file value="AppLog.xml" />
        <appendToFile value="true" />
        <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
        <layout type="log4net.Layout.XmlLayoutSchemaLog4j" />
  </appender>
  <root>
        <level value="WARN" />
        <appender-ref ref="XmlSchemaFileAppender" />
  </root>

---