I was hoping to be able to do this too :confused:
There will be so many headaches involved apparently :p - I've read in loads of places, the best way of doing things on a Mac is just to run it in VMware Fusion/ under VirtualBox.
You can download a preconfigured virtual machine version from the BackTrack website with VMware Tools + all the other Mac drivers installed by default. These do not come with the standard .iso version. Everything should then work as expected! :)
There isn't really that many advantages between dual/ triple- booting compared to running Backtrack as a virtual machine. Backtrack doesn't take up too much ram as a virtual machine on your Mac, so it's probably just easiest to do things that way... :(
Hope this kind of helps! :p
Maybe someone else who knows what to do may be able to help us both out and write a tutorial for everyone on how to install the Backtrack ISO and set up all the drivers on a Mac as another partition on the hard disk :) It's a lot of work apparently though and may not even be possible atm, so let's not get too excited!... :p