2008 and 2012 are not incompatible.
It may be a matter of how your IT folks approached this - AC will not give out the sa [admin] password, but they will cooperate to get AC installed on a full version of SQL. At that point they won't offer support for operating the full SQL environment.
So, if you want both, you may want to consider installing AC as a virtual server on your existing server so the two remain separate.
