I only had the issue you describe once and was able to remove the keys in the registry but I understand that it's a tricky business and a way you would not prefer to do taking into account the possible negative effects it can cause when you remove the wrong keys. I am sorry to say I dont know any other way.
You could consider raising a PMR at IBM or try contacting someone at IBM who is able to help you further.
Maybe someone else on the forum has dealt with the same issue an did not take the effort yet to respond. Maybe that person can stand up know and help you out; I hope so