How to put custom ClassLoader to use?

Hello all and thanks for the attention! I have a problem that must both be easy and obvious, yet I am stuck.

I want to deliver dynamically created Java classes to be used by a 3rd party library via a custom ClassLoader.

Now my problem is: How do I set my custom ClassLoader to be used to load this classes when I do not load them directly myself?

I thought when I used my ClassLoader to load a certain class, it became this class's ClassLoader, and all classes loaded from that class would be channeled through my ClassLoader.

I created a custom ClassLoader, following this official tutorial: http://java.sun.com/developer/onlineTraining/Security/Fundamentals/magercises/ClassLoader/help.html.

public class DynamicClassloader extends ClassLoader {

    private Map<String, Class<?>> classesMap = new HashMap<String, Class<?>>();

    public DynamicClassloader(ClassLoader parent) {
        // Also tried super(parent);
        super(sun.misc.Launcher.getLauncher().getClassLoader());
    }

    // Adding dynamically created classes
    public void defineClass(String name, Class<?> clazz) {
        classesMap.put(name, clazz);
    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        // load from parent
        Class<?> result = findLoadedClass(name);
        if (result != null) {
            return result;
        }
        try {
            result = findSystemClass(name);
        } catch (Exception e) {
            // Ignore these
        }
        if (result != null) {
            return result;
        }
        result = classesMap.get(name);
        if (result == null) {
            throw new ClassNotFoundException(name);
        }
        return result;
    }
}

I wanted to use this somewher