For more information on MS Help Viewer 1.x see http://helpware.net/mshelp3/

Help is installed by the book. Each book can contain one or more packages. A package is either a .mshc help file, or a signed .cab file that contains a single .mshc help file (with or without a .mshi index file).

Note: Microsoft .cab files contain a .mshc and a pre-compiled .mshi index file. Cab files can be signed and installed silently. Currently Microsoft have no mechanism for helping you to creating an index file. Although you can probably just copy one out of the Help Library data store. See Add an Index to your .Cab Help Package.