Look at the text file called "mssolver.ini", which can be found in same directory as the "mssolver.exe".
The syntax should seem very simple to you, you will see the links to images which are contained in the "images" directory.
So, for making your own config you need to add a key "confN = YourConfName" in section "[configs]",
and then add the "[YourConfName]" section itself, setting all the fields using the existing configs as the examples. Also you need to add the images of open fields... That is done easily by playing the game manually, taking the screenshots, and... using crop in Paint for Windows.