This is a patch to run Southernmost Combine 1.25 Ultimate edition using Source SDK 2013 SP, instead of Half-Life 2 Ep2.
Want to play the mod but dont own Half-Life 2 Episode 2? Try this patch!
to install it you first need previously install Southernmost Combine 1.25 Ultimate located at Moddb.com
Then, unpack the content of this file inside the root Southernmost folder, it will replace the original gameinfo.txt and will add the bin subfolder.
Enable Beta "upcoming" in Source SDK 2013 Single Player´s properties, then restart Steam.
This fix was proposed by an user, H4uja2. I can´t warranty it works, because it´s never been broken for me in the first place.
Please let other players know if this works.