Woot, this is awesome! Then I can pre-view Left 4 Dead 2 Maps and Campaigns inside the game and download them directly to the Server.
This really helps a lot, if someone suggests a custom map for L4D2, which is not on the Server.
EDIT: I dunno if I did something wrong, re-following the instructions, but the plugin FAILED to load on my L4D2 server so far.
EDIT 2: Left 4 Dead 2 sadly is not supported, because system2 is not working with it