Finally released!! Waiting so long…
Here is the link for the docs and sample code etc

Solution for Hosted Messaging and Collaboration v4.5

Here is the link for the updated SDK doc.

Use HMC 4.5 to address several critical customer scenarios, including:

Messaging and management of e-mail messages, attachments, and business tasks. HMC 4.5 lets you extend your reach to SMB customers, small office and home office customers, and even individuals. Services can range from reliable, scalable e-mail functionality to additional storage, shared calendars and contacts, and hosting of personal domains.

Direct, multichannel communications. Using the contact information stored in Microsoft Active Directory®, Microsoft Office Communications Server 2007 manages all communications, including e-mail, instant messaging, audio, video, Web conferencing, and PC-to-PC calling. Office Communications Server 2007 enables presence, so people can determine whether others are available before contacting them in the most practical way–for example, by instant messaging, a phone call, or a video conference.

Secure, productive collaboration and sharing of digital assets. Windows SharePoint Services gives you a way to host team Web sites that can become a customer’s preferred avenue for effective teamwork and content exchange.

The table below highlights the advantages of the key elements of HMC 4.5.