getting army (AKO-CAC enabled) Enterprise Email on my Mac

I am in the military, and trying to figure out how to get to the new enterprise email using my mac. I have OS lion, and was able to get to it before (earlier OS). But since upgrading, cannot.

Is there something i need to load to be able to use my CAC card to reach enterprise email? If there isnt a fix, mac will no longer be usable for soldiers that need to access enterprise email daily.