Microsoft Forefront Unified Access Gateway (UAG) Update 2 is an update to Forefront UAG that provides the following functionality updates and other improvements:

• Citrix publishing support—Forefront UAG fully supports Citrix Presentation Server 4.5 and its replacement Citrix XenApp 5.0.
• Citrix client computer support—Forefront UAG supports client computers with 64-bit operating systems accessing Citrix XenApp applications.
• Client Components—The Forefront UAG SSL Application Tunneling component is now supported on 64-bit Windows 7 operating systems for 32-bit applications.
• Virtual Desktop Infrastructure (VDI)—Forefront UAG fully supports publishing remote desktops using VDI.
• SSTP user and group access control—Forefront UAG now provides a finer authorization mechanism allowing administrators to authorize individual users or groups for SSTP access.
• SSL handshake—Forefront UAG now provides better handling of the SSL handshake including the case when the application server requires client certificate credentials for the negotiation.
• MAC address support—Forefront UAG Network Connector supports a wider range of network adapters with a larger valid MAC address range.

See the rest of the instructions and information @ http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9dcccebc-accb-4229-901a-792cc66791de.