The key for non-Server versions of Windows is

  HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Kerberos
    AllowTGTSessionKey = 0x1 (DWORD)

This is set by the KFW installers.  

Although we are not currently setting the MSLSA as the default cache I
am going to close this ticket at this point because significant progress
has been made to improve the interoperability of the LSA cache.  See
ticket 2705.