After the resources I have the same problem with the classes that are needed from MetaWidget.
The fact is that from the configuration it must load a class inside my module/plugin, but to lookup the class it uses the org.jboss.forge.forge-scaffold... module, which of course know nothing about my custom classes.
Now the solution is to override the lookupClasses, but am I doing something wrong ?? There is a way to let "system" modules see my custom classes ??