Actually, there is a workaround to provision AAD as identity provider in ACS. http://www.cloudidentity.com/blog/2013/10/03/provisioning-a-windows-azure-active-directory-tenant-as-an-identity-provider-in-an-acs-namespacenow-point-click/
Basically, what has to be done is add the FederationMetadata.xml url when AAD is created as Identity provider in ACS.
After (in VS 2012) there is anew utility Identity and Access that will let you choose the IPs, and will create a new group in ACS, in which it has to be add the claim(s) transformation rule that we need (it is said in the post should be checked in code because claim changes)