slope limit when going downhill

I’ve been searching over the forums and entire web for a few days now and cant seem to find any help with an issue i am trying to resolve.

I’m making a 3rd person game in unity and so far its running great, only problem i am having is that i don’t want my character to be able to walk off of cliffs and other extreme slopes when going downhill. The character controller doesn’t seem to have a setting for this, so i was wondering if anyone in the community has done something like this?

You could check this out, but I haven’t tried it myself. Not sure if it has anything preventing going downhill.
http://forum.unity3d.com/viewtopic.php?t=41240