I installed a Xamarin trial and then upgraded to the business license. After installing the trial version, I installed Visual Studio 2012. I downloaded and ran the Windows installer (after installing 2012). Now, the "Xamarin Account" option appears under Tools in VS2010, but NOT in VS2012. I have rerun the installer a couple of times (as Admin), and even tried manually installing the msi files from the installer log. VS2012 doesn't seem to be getting the plugin.
I have deleted my trial license from the MonoForDroid\License directory.