if you've downloaded the sgn_61_sfx.exe from the Sophos Download portal, you will find the Management Center package under C:\sgn_61\SGEnterprise\Installers\Backend installers\SGNManagementCenter.msi, after extracting the exe-archive.
if you've downloaded the sgn_61_sfx.exe from the Sophos Download portal, you will find the Management Center package under C:\sgn_61\SGEnterprise\Installers\Backend installers\SGNManagementCenter.msi, after extracting the exe-archive.