Enhance Enum generation to support custom business logic, as GAS already supports for classes via the 'Base' pattern?

There are times you want to add business logic to enums. Right now, if any custom logic is added to the generated enum classes it will be overwritten.

The 'Operation' enum from from the Java Language Guide is a good conceptual example of the need (http://java.sun.com/j2se/1.5.0/docs/guide/language/enums.html, about halfway down the page).