You'll need to sit SA Air Law,a RT exam, a combined GFT/Navex and about R250 for a Validation- you'll then have to wait 2-3 months for the paperwork to be returned fron Pretoria.
The validation will only be valid until the expiry of your UK/JAR Medical- get a SA Medical to get the full year !
I found 'the system' alot easier in Florida.