For this to work for vs, you have to do a couple things.
Unzip the package, install the new deadontime2.vpk
Then copy the "maps" folder to 
32bit Drive:\Program Files\Steam\steamapps\common\left 4 dead 2\left4dead2
64bit Drive:\Program Files (x86)\Steam\steamapps\common\left 4 dead 2\left4dead2

Now you should be able to play this in VS.