I haven't had the time to install it and find out for myself and Microsoft is extremely vague about it.
It does not. The following clip from the Server 2012 Essentials blog sums it up:
With Essentials 2012, there are three deployment options for messaging and collaboration services for which we provide an integrated management experience:
On-Premises. Essentials 2012 contains integration with an on-premises Exchange Server running on a second server, which can be either physical or virtual.
Office 365. Essentials 2012 builds on the previous Office 365 Integration Module for SBS 2011 Essentials. This option is now part of the core product (no separate download is required) and it allows customers that have an Office 365 account to use this service for their email.
Hosted Exchange. Hosted Exchange providers can offer add-ins to Essentials 2012 that will allow customers to select this option. We know that there are many different types of hosted email providers. While we have focused on hosted Exchange email providers, we engineered the product to be email service agnostic which allows non‑Exchange based email providers to be integrated through this mechanism (note that this specific feature is not available in the beta).