MapSetToolKit is a tool for creating mapsets and installing them into MapSource, written by Cypherman1. It is available at here. It is also distributed with the Ibycus maps, in the Advanced directory.
MapSourceToolKit can be confusing as it has many fields and controls, while only a few are needed to install the Ibycus maps.
First, note that the actual maps are in a directory called "IMGS" below the mapset directory.
Here is the initial screen of MapSetToolKit. It is not necessary to fill in any fields on the main screen - simply click on the "Install" button below the listbox on the right.
A popup box will appear. Enter a registry name. Select the tdb and img files from the mapset directory. Note that there are two of each in the Ibycus version 4.0. Use the ones shown - the others relate to a set of road maps. Ensure that the maps directory ("IMGS") is selected, as opposed to the higher level mapset directory. Then click on the "INSTALL" button.
The install will finish quickly with a conformation box. The listbox will then show an entry for the Ibycus maps.
Move the listbox slider to the right and it can be seen that the maps total around 4 GB.