How to Make a Zombie Survival Map

So I am thinking about making a map for the gamemode Zombie Survival.

I was wondering if anyone knew exactly what you have to do to make the map work with the gamemode settings.

Plus also if anyone had any tips for what makes a good ZS map.

Here’s some tips, and gamemode specific entities (most of these entities aren’t in the latest public release):
http://www.noxiousnet.com/forums/index.php?topic=2373.0