MMC 2.0 Registry Entries
To enable a snap-in to be added to a console file, the snap-in (or the snap-in's setup program) must add the appropriate entries in the MMC registry key (HKEY_LOCAL_MACHINE\Software\Microsoft\MMC). Usually, you implement registry code to make the appropriate MMC entries for your snap-in in the DllRegisterServer function (or in a registrar script if you are using the ATL Registrar) of your snap-in's in-process server DLL.
The entries are determined by the type of snap-in (stand-alone or extension).
There are two main keys:
Contains information about each snap-in that can be added to an MMC console file. Both stand-alone and extension snap-ins must be added here.
Contains information about the extensions for each node type.