We have a lot of DCs/AD based on Win2008R2 and is most of then, we have the EAD-MD5 enabled by registry change (see the article http://support.microsoft.com/kb/922574/en-us)
The key is: SYSTEM\CurrentControlSet\Services\RasMan\PPP\EAP\4
The official answer is about Win2008, but it works in Win2008R2 too with no problems. And based on the registry change we deployed our 802.1X solution, RADIUS and Alcatel IP phones flawlessly.
And what about Win2012R2? We´re about to upgarde our DCs and i would like to know if the change is still effective or if there is another workaround, or to knwo if there is something i need to know about that.