I don't know who has played L4D2 here so far but you probably realized the L4D2 theme music + chimes you hear when a horde is summoned sound different for each campaign to fit the campaign's atmosphere more.
Dark Carnival's sounds eerie and spooky
The Parish's sounds southern with a bit of a jazz feeling
etc
You see what I mean. Now I plan to ask Chet Faliszek from Valve (I've been in contact with him a bunch of times about mapping and shit) if Valve would allow me to take the L4D2 theme music and "edit" it so it also fits my campaign's theme more.
Since I want to create a scary/haunted one, I'd like to remix the original theme into something creepier but the original theme must still be recognizable.
Now my question is: if Valve were to give me permission (and I don't see why they would not since I'm not taking songs from other sources but the game itself), are there any composers/sound specialists here who are willing to help me do this? I don't have any experience with composing music...