Validations
I am in the same boat with the CAA - validation of an FAA comm. I have spoken to them about the new regs. They told me that if I have had the validation for more than 3 years and done more than 750 hours in that time then the licence would be converted directly into a South African one. (I'm not sure if a flight test would be needed now that I think about it, it didn't sound like it). If you don't meet these requirements, time to hit the books - all the exams and flight tests!
If you have only renewed it once I don't think they will accept it but give them a call and ask them. Once you can get them to answer their phones they are reasonably helpful.