XBMC Media Scrapping - FTP / NAS Source

I have added an FTP Source and use my MacBook to connect to media NAS at home
I can access the source ok and play media but media scrapping is not working.

Looking at my MacBook I only have the Universal Scraper listed and am unable to
install addons .... has anyone produced a guide to get this working

MacBook - Mountain Lion 10.8.3