You should have no problems at all when using the compiled DLL, either.
ObjectManager.Memory is an instance of BlackMagic, and will therefore have an ID property.
The whole point of having that very instance in the ObjectManager is to keep things centralized, for clarity's sake. So if you would have four instances of WoW running, you tell BlackRain which one you want to use, then BlackRain creates an instance of BlackMagic at ObjectManager.Memory, and you only use the Memory member inside any projects after that.