There is no mission file as far as I can see in the zip file. Only an Addon.ima file. Shouldn't there be a mission file too? I hope that this isn't a stupid question. I tried using LOMAN to install it and nothing shows up in the menu after I download the RAR packet. MODMAN doesnt recognize it at all.
You should probably mention somewhere that it is necessary to create a sub folder in the Viggen folder called "blue". That is the folder that you must extract to. Otherwise if you just extract to the Viggen folder it doesn't show up.