Using Scratch to load program to LittleBits Arduino

I am exploring the possiblity of teaching 5th Graders how to use Scratch to program LittleBits.  In order to make this happen a number of things need to be place.  I've followed this guide: http://goo.gl/9GVLKb by khanning.  I've not been successful.  Is there anyone who has had success in connecting Scratch to the LittleBits Arduino module?  I have Mac lab.  Thanks!