All you need to do is to add "cloak:" prefix to entity name, but it works only with CustomAmmoPickup class. Also, only players with sfwcl can see the effect. :)
Here's list of all available prefixes:
frozen:
dynfrozen:
wet:
cloak:
fx: -- for spawning effects
https://github.com/diznq/sfwcl/blob/master/src/lua/Files/main.lua#L321
Maybe later I can add support for any classes client-side, but problem is it could be heavy on performance to iterate all the entities in-game to check which one need update and which ones don't :D
Zi; can you make SSM SafeWriting Support XML for level setup? it would make level setup 100% easier cause you would just have to copy the leveldata.xml from level.pak to mapsetup folder :D
so you can create a map, save it and just copy the leveldata.xml contend to the levelsetup.xml file!