I don't have the answer for you, but I do know that it's not a good idea to modify your project's .aj files, as these are managed by Roo (which might decide to remove your changes at some later point). If you want to customise your controllers' behaviour, the safe approach is to "push in" the relevant elements (methods, etc) from the .aj file into the .java file, and make your changes there. You might even find that this makes your annotations work properly.
Andrew Swan
"Now is the EJB of our discontent made glorious Spring"