You'll need Pro Tools 10 to run 'officially' on OSX 10.8
Saying that, apparently PT8.0.5 will work in some circumstances.
Try these drivers to get it recognised:
http://secure.digidesign.com/service...&localeCode=en
You'll be able to get the mbox working with those drivers - however, you'll need an updated version of pro tools if you want to use that as a DAW.