Thanks for your comments, delMar.
The Covert Mission files have been renamed by me to follow the original WC naming convention. ie. WC file extensions are .000; Secret Mission 1 files are .001; and Secret Mission 2 files are .002. So, for Covert Missions (SM1.5) I set the file extensions to .015.
briefing.sm15 ~~~> briefing.015
camp.sm15 ~~~~> camp.015
module.sm15 ~~~> module.015
title1.sm15 ~~~~~> titl15.vga
Then, within the Secret Missions 2 executable file (sm2.exe) I used a hex editing program to change the .002 extensions for the three files to .015 and the title screen file name from title1.vga to titl15.vga. I saved my changes to a new file named cm15.exe.
Using this method you can place the new Covert Mission files in the gamedat folder along with the Secret Missions 2 files. Starting the game with cm15.exe brings you to the Covert Missions title screen and off you go from there.
Please download the archive from my previous post again. I had forgotten that I had changed the artist's names... now only the Covert Missions changes are incorporated. Thanks!
Thanks for your effort. Is there also a variant for the gog variant, since it has its own exe file integrated and is not run manual in dosbox ?