Applied a patch provided by frede...@buelthoff.name at http://code.google.com/p/bpep/issues/detail?id=9:

"Additions:
- Added the action to the main "Source" menu
- Activated the action binding and changed it to Ctrl + Alt + B
- Pressing enter in the builder dialog starts the generation process
- Added an option (activated by default) to add a copy constructor to the generated builder (takes the respective bean and copies its members)

Changes:
- An existing builder class implementation will be replaced instead of appending a new class (custom changes to the class will therefore be lost)"
Refactored some of the new functionality into their own methods, for clarity.
Changed the method parameter names in the generated Builder class, as with strict enough compiler settings in Eclipse (Preferences -> Java -> Compiler -> Errors/Warnings -> Name shadowing and conflicts) the previous parameter name format caused lots of errors or warnings ('The parameter xxxx is hiding a field from type Yyyy.Builder').
Changed the field access level modifiers of a Builder to package-private, i.e. removed the 'private' keyword. This is to stop Eclipse from complaining in the builder-constructor of the containing class that 'Read access to enclosing field Yyyy.Builder.xxxx is emulated by a synthetic accessor method', which it will do with strict enough compiler settings.
The Builder class cannot access a private constructor of the containing class if the compiler settings are strict enough, so changed the constructor into package-private.
Refactored some pieces of code into their own methods, for clarity.
Merge pull request #1 from ZeroOne3010/master

That one patch + my own modifications