In this blog post Peter Karich shares his own configuration of Maven deps when you use db4o with the Transparent Activation feature: http://karussell.wordpress.com/2010/05/20/db4o-via-maven/

Once you use Peter's POM file all you have to do is:

config.add(new TransparentActivationSupport());

// configure db4o to use instrumenting classloader
config.reflectWith(new JdkReflector(Db4oHelper.class.getClassLoader()));
config.diagnostic().addListener(new DiagnosticListener() {

   @Override
   public void onDiagnostic(Diagnostic dgnstc) {
      System.out.println(dgnstc.toString());
   }
});