Here is the article on how to install the update on the EX47X machines.

When HP released the HP MediaSmart Server 2.5 Update for the EX48x machines, they also ^[1] announced the full software would not be available to first generation users due “to hardware differences” anhd “the underlying software architecture”. Based on that statement, Nigel Wilks (Cougar) and Alex Kuretz (Yakuza) started work on a way^[2] to make the update available to EX47x owners, dubbed “SanEncore” after the code names for the EX47x (San Juan) and the EX48x (Encore).

Cougar and Yakuza have also developed a Windows Home Server Add-In to fake the Update package into thinking it is running on a 2.1 machine, and handles some of the missing configuration items so that the 2.5 update is sucesful.